Hydraulic Machines Pune University MCQs
Hydraulic Machines Pune University MCQs
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Turbines-1”.
1. Hydraulic energy is converted into another form of energy by hydraulic machines. What form of energy is that?
a) Mechanical Energy
b) Electrical Energy
c) Nuclear Energy
d) Elastic Energy
Answer: a
Explanation: Hydraulic machines firstly convert the energy possessed by water into mechanical energy. Later it can be transformed into electrical energy.
2. In hydraulic turbines, inlet energy is greater than the outlet energy.
a) True
b) False
Answer: a
Explanation: The operating member which receives energy at the inlet should be more compared to energy at the outlet.
3. Which principle is used in Hydraulic Turbines?
a) Faraday law
b) Newton’s second law
c) Charles law
d) Braggs law
Answer: b
Explanation: A Hydraulic Machine uses the principle of momentum which states that a force is generated which is utilized in a turbine.
4. Buckets and blades used in a turbine are used to:
a) Alter the direction of water
b) Switch off the turbine
c) To regulate the wind speed
d) To regenerate the power
Answer: a
Explanation: Turbines use blades and buckets to alter the direction of water. It is used to change the momentum of water. As momentum changes, force is produced to rotate the shaft of a hydraulic machine.
5. _______________is the electric power obtained from the energy of the water.
a) Roto dynamic power
b) Thermal power
c) Nuclear power
d) Hydroelectric power
Answer: d
Explanation: The energy from the energy of water is also called hydro power. The electric power so obtained is known as hydroelectric power.
6. Which energy generated in a turbine is used to run electric power generator linked to the turbine shaft?
a) Mechanical Energy
b) Potential Energy
c) Elastic Energy
d) Kinetic Energy
Answer: a
Explanation: The kinetic and potential energies produced are converted to some useful mechanical energy. This part of energy is available to the turbine shaft.
7. Hydraulic Machines fall under the category :
a) Pulverizers
b) Kinetic machinery
c) Condensers
d) Roto-dynamic machinery
Answer: d
Explanation: Hydraulic Machines use the principle of rotation of blades to alter the speed of water. Hence fall under roto dynamic machinery.
8. Which kind of turbines changes the pressure of the water entered through it?
a) Reaction turbines
b) Impulse turbines
c) Reactive turbines
d) Kinetic turbines
Answer: a
Explanation: Reaction turbines which act on water try to change the pressure of the water through its motion.
9. Which type of turbine is used to change the velocity of the water through its flow?
a) Kinetic turbines
b) Axial flow turbines
c) Impulse turbines
d) Reaction turbines
Answer: c
Explanation: In Impulse turbines, potential energy is utilized to convert as kinetic energy thereby changing the velocity of the water through its process.
10. Which type of turbine is a Francis Turbine?
a) Impulse Turbine
b) Screw Turbine
c) Reaction turbine
d) Turgo turbine
Answer: c
Explanation: Francis turbine is a reaction turbine as it changes the pressure of water through its process. Hence it cannot be an impulse turbine.
11. How many types of Reaction turbines are there?
a) 5
b) 4
c) 3
d) 9
Answer: a
Explanation: There are five types of reaction turbines namely VLH, Francis, Kaplan, Tyson, Gorolov helical turbine.
12. Turgo Turbine is an impulsive turbine.
a) True
b) False
Answer: a
Explanation: In a turgo turbine, velocity of water changes with due respect. Hence it is an Impulse turbine.
13. Which kind of turbine is a Fourneyron Turbine?
a) Inward flow turbine
b) Outward flow turbine
c) Mixed flow turbine
d) Radial flow turbine
Answer: b
Explanation: In a Fourneyron turbine, the flow is centrifugal type. The flow is outwards from the centre to the periphery.
This set of Hydraulic Machines Interview Questions and Answers focuses on “Turbines – 2”.
1. Maximum Number of jets, generally, employed in an impulse turbine without jet interference can be?
a) 2
b) 3
c) 4
d) 6
Answer: d
Explanation: Equating equations of initial jet velocity and energy of a turbine, we get the minimum number of jets to be 6.
2. The overall efficiency of a reaction turbine is the ratio of
a) Actual work available at the turbine to the energy imparted to the wheel
b) Work done on the wheel to the energy actually supplied to the turbine
c) Power produced by the turbine to the energy actually supplied by the turbine
d) Actual work available at the turbine to energy imparted to the wheel
Answer: a
Explanation: The overall efficiency of any turbine will be mechanical efficiency * hydraulic efficiency.
3. In a reaction turbine, the draft tube is used to _________
a) To increase the head of water by an amount that is equal to the height of the runner outlet above the tail race
b) To prevent air to enter the turbine
c) To increase pressure energy of water
d) To transport water to downstream
Answer: a
Explanation: A draft tube influences performance of a turbine. It is located below the runner to decelerate flow velocity.
4. In reaction turbine hydraulic efficiency is______________
a) Ratio of actual work at the turbine to the energy imparted to the wheel
b) Ratio of work done on the wheel to energy that is supplied to the turbine
c) Ratio of power produced by the turbine to the energy actually supplied by the turbine
d) Ratio of Work done on the wheel to the energy actually supplied to the turbine
Answer: b
Explanation: In turbines, overall efficiency is the product of hydraulic and mechanical efficiencies. Here the hydraulic efficiency is ratio of work done to head of water.
5. Consider an inward flow reaction turbine, here, water _______
a) Flows parallel to the axis of the wheel
b) Enters the wheel at the outer periphery and then flows towards the centre of the wheel
c) Flow is partly radial and partly axial
d) Enters at the centre of the wheel and then flows towards the outer periphery of the wheel
Answer: b
Explanation: In any inward reaction flow turbine, water enters the outer periphery towards the centre of the wheel.
6. The working of which of the following hydraulic units is based on Pascal’s law?
a) Air lift pump
b) Hydraulic coupling
c) Hydraulic press
d) Jet pump
Answer: c
Explanation: Pascal’s law can be described as the rate of flow of volume is constant. Hydraulic press uses similar principle.
7. Which kind of turbine is a Pelton Wheel turbine?
a) Tangential flow turbine
b) Radial flow turbine
c) Outward flow turbine
d) Inward flow turbine
Answer: a
Explanation: Tangential turbine is one which water strikes runner in direction of the tangent to wheel of the turbine.
8. IN what type of turbine water enters in radial direction and leaves axial direction?
a) Tangential flow turbine
b) Axial flow turbine
c) Outward flow turbine
d) Mixed flow turbine
Answer: d
Explanation: Only in a mixed flow turbine, water enters in radial direction and leaves axial direction.
9. How many types of turbines can you classify on the basis of direction of flow through runner?
a) 6
b) 3
c) 4
d) 7
Answer: c
Explanation: There are 4 types of turbines, namely tangential, radial, axial, mixed flow turbines.
10. Into how many types can you classify radial flow turbines?
a) 4
b) 3
c) 6
d) 2
Answer: d
Explanation: We can classify radial flow turbines into 2 types, namely inward radial flow and outward radial flow.
11. Into how many types can you classify turbines on basis of head at inlet?
a) 3
b) 4
c) 6
d) 5
Answer: a
Explanation: We can classify turbines into 3 types on basis of head. Into high head, low head, medium head discharged.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Heads in a Turbine”.
1. Among the following which turbine requires more head?
a) Pelton Turbine
b) Kaplan Turbine
c) Francis turbine
d) Tube Turbine
Answer: a
Explanation: Except Pelton remaining are reaction turbines, in impulse pressure energy is constant and only available energy is kinetic energy which is directly proportional to head.
2. Total head of turbines is_______
a) Pressure head + Static head
b) Kinetic head + Static head
c) Static head + Pressure head
d) Pressure head + Kinetic head + Static head
Answer: d
Explanation: Generally total is calculated as sum of pressure head, static head and kinetic head.
3. Head under which Kaplan turbine is operated______
a) 10-70 meters
b) 70 -100 meters
c) 100-200 meters
d) Above 200 meters
Answer: a
Explanation: Kaplan turbine is reaction turbine and it operates at low head 10-70 meters and output power is 5-200 MW.
4. Head under which Francis turbine is operated?
a) 10-70 meters
b) 70-100 meters
c) 100-200 meters
d) 40-600 meters
Answer: d
Explanation: Francis turbine is also reaction turbine but pressure energy is less when compared with Kaplan turbine. Hence head is between 40 and 600 meters.
5. The turbine is preferred for 0 to 25 m head of water?
a) Pelton wheel
b) Kaplan turbine
c) Tube turbine
d) Francis turbine
Answer: b
Explanation: Kaplan is reaction turbine and its range of operation is between 10-70 meters which has output range between 5-200 MW.
6. Under what head is Pelton turbine operated?
a) 20-50 meters
b) 15-2000 meters
c) 60-200 meters
d) 50-500 meters
Answer: b
Explanation: Pelton turbine is an impulse turbine only energy available is kinetic energy which is proportional to head, hence it requires high head. Theoretically there is no limit to max value of head.
7. _____________ is difference between head race and tail race.
a) Gross head
b) Net head
c) Net positive suction head
d) Manometric head
Answer: a
Explanation: Gross head is the difference in elevation of water levels of fore bay and tail race.
8. The head available at inlet of turbine is ____________
a) Net positive suction head
b) Gross head
c) Net head
d) Manometric head
Answer: c
Explanation: It is the available effective head used for production. This is also called as static gross head.
9. Head lost due to friction is given by k*f*L*v*v/D*2g where f- friction coefficient, L- length of pen stock, D- diameter of penstock and” k” is constant and its value is ____________
a) 2
b) 3
c) 4
d) 5
Answer: c
Explanation: The constant determined from the given formula is 4.
10. The difference between gross head and friction losses is ____________
a) Net head
b) Gross head
c) Manometric head
d) Net positive suction head
Answer: a
Explanation: Net head is the effective head used to calculate power production. It includes the elimination of frictional losses from the gross head.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Efficiencies of a Turbine”.
1. _____________ is defined as ratio between power delivered to runner and power supplied at inlet of turbine.
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: c
Explanation: Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine.
2. Which among the following which is not an efficiency of turbine?
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Electrical efficiency
Answer: d
Explanation: Electrical efficiency is ratio of work output and electrical power input to electrical machine but turbine is a hydraulic machine which consists of only mechanical, volumetric and hydraulic efficiencies.
3. The ratio of power at the shaft of turbine and power delivered by water to runner is known as?
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: a
Explanation: Due to mechanical losses, power available at shaft of turbine is less than power delivered to the runner of turbine. Hence ratio of power at the shaft of turbine and power delivered by water to runner is known as mechanical efficiency.
4. The product of mechanical efficiency and hydraulic efficiency is known as?
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: d
Explanation: Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency.
5. Among the following which turbine has highest efficiency?
a) Kaplan turbine
b) Francis turbine
c) Pelton turbine
d) Propeller turbine
Answer: a
Explanation: Kaplan is inward flow reaction turbine and is operated under head less than 60 meters. The vanes attached to hub are adjustable and Kaplan is mainly operated in location where large quantity of water at low head is available.
6. _____________ is ratio of volume of water actually striking the runner and volume of water supplied to turbine.
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: b
Explanation: Volumetric efficiency is ratio between volume of water actually striking the runner of turbine and volume of water supplied to the turbine.
7. In the expression for overall efficiency of turbine, which is p/, where “k” is known as ___________
a) Density of liquid
b) Specific density of liquid
c) Volume of liquid
d) Specific gravity of liquid
Answer: a
Explanation: Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency. Its expression is given by p/ where k is density of liquid.
8. The expression for maximum hydraulic efficiency of pelton turbine is given by?
a) /2 where k is outlet blade angle
b) /2 where k is outlet blade angle
c) /2 where k is outlet blade angle
d) /2 where k is outlet blade angle
Answer: a
Explanation: Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine. Its maximum value is obtained by replacing u=v/2 and it is /2 where k is outlet blade angle.
9. To obtain maximum hydraulic efficiency of pelton turbine, blade velocity should be ___________ Times the inlet velocity of jet.
a) Half
b) One quarter
c) Twice
d) Thrice
Answer: a
Explanation: Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine. This efficiency will be maximum when differentiating it with “u” and it is obtained as u=v/2.
10. Among the following which turbine has least efficiency?
a) Pelton turbine
b) Kaplan turbine
c) Francis turbine
d) Propeller turbine
Answer: a
Explanation: Pelton turbine is an impulse turbine, where there is no theoretical limit for head due to high head there is loss due to friction when water passing through penstocks hence its efficiency is less.
11. The ratio of volume available at shaft of turbine and power supplied at the inlet of the turbine
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: d
Explanation: Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Classification of Hydraulic Turbines-1”.
1. A hydraulic coupling belongs to the category of________
a) Energy absorbing machines
b) Energy generating machines
c) Power absorbing machines
d) Energy transfer machines
Answer: d
Explanation: Hydraulic coupling is a device used for transmitting rotation between shafts by means of acceleration and deceleration of hydraulic fluid.
2. The electric power which is obtained from hydraulic energy____________
a) Thermal power
b) Mechanical power
c) Solar power
d) Hydroelectric power
Answer: d
Explanation: Hydroelectric power is generated by using hydraulic machines. Potential energy of water is converted to mechanical energy which is connected to dynamo to generate electrical energy.
3. At present which is cheapest means of generating power_____________
a) Thermal power
b) Nuclear power
c) Hydroelectric power
d) Electric Power
Answer: c
Explanation: Hydraulic energy is renewable source of energy in which Potential energy of water is converted to mechanical energy which is connected to dynamo to generate electrical energy.
4. Pipes of largest diameter which carry water from reservoir to the turbines is known as_____________
a) Head stock
b) Tail race
c) Tail stock
d) Pen stock
Answer: d
Explanation: Penstocks are channels which transport water from reservoir to turbines which are usually made up of cast iron or concrete.
5. Pen stocks are made up of _____________
a) Steel
b) Cast iron
c) Mild steel
d) Wrought iron
Answer: a
Explanation: Penstocks are channels which transport water from reservoir to turbines which are usually made up of cast iron or concrete.
6. ____________ is an inward radial flow reaction turbine.
a) Pelton turbine
b) Kaplan turbine
c) Francis turbine
d) Propeller turbine
Answer: c
Explanation: Kaplan and propeller are outward axial flow reaction turbines but Francis is outward radial flow reaction turbine.
7. The important type of axial flow reaction turbines are ______________
a) Propeller and Pelton turbines
b) Kaplan and Francis turbines
c) Propeller and Francis turbines
d) Propeller and Kaplan turbines
Answer: d
Explanation: Axial flow turbine is a turbine in which water flows axially outwards and turbines fall into this category are propeller and Kaplan turbines.
8. ______________ is a axial flow reaction turbines, if vanes are fixed to hub of turbine.
a) Propeller turbine
b) Francis turbine
c) Kaplan turbine
d) Pelton turbine
Answer: a
Explanation: Axial flow turbine is a turbine in which water flows axially outwards, if vanes are fixed to hub of turbine it is known as Propeller turbine but if vanes are free to move it is known as Kaplan Turbine.
9. Francis and Kaplan turbines are known as _______
a) Impulse turbine
b) Reaction turbine
c) Axial flow turbine
d) Mixed flow turbine
Answer: b
Explanation: Francis and Kaplan are reaction turbines because pressure energy of water changes when it enters the rotor.
10. Specific speed of reaction turbine is between?
a) 5 and 50
b) 10 and 100
c) 100 and 150
d) 150 and 300
Answer: b
Explanation: Specific turbines of reaction turbines such as Francis and Kaplan lie under the range 10-100.
11. Impulse turbine is generally fitted at ______________
a) At the level of tail race
b) Above the tail race
c) Below the tail race
d) About 2.5mts above tail race to avoid cavitations.
Answer: b
Explanation: Impulse turbine is fitted above the tail race because in impulse turbines, the pressure energy must convert into kinetic energy for usage.
This set of Hydraulic Machines Questions and Answers for Freshers focuses on ” Classification of Hydraulic Turbines – 2″.
1. Hydraulic turbines are classified based on ____________
a) Energy available at inlet of turbine
b) Direction of flow through vanes
c) Head at inlet of turbine
d) Energy available, Direction of flow, Head at inlet.
Answer: d
Explanation: Hydraulic Turbines can be classified on any basis like energy supplied, direction of flow, and head at inlet.
2. Impulse turbine and reaction turbine are classified based on?
a) Type of energy at inlet
b) Direction of flow through runner
c) Head at inlet of turbine
d) Specific speed of turbine
Answer: a
Explanation: In impulse turbine, pressure energy firstly converts into kinetic energy but in reaction turbine pressure change of water is present only when it passes through the rotor of the turbine.
3. Tangential flow, axial flow, radial flow turbines are classified based on?
a) Type of energy at inlet
b) Direction of flow through runner
c) Head at inlet of turbine
d) Specific speed of turbine
Answer: b
Explanation: Different types of flow of water classify turbines into tangential, axial, radial flow.
4. High head, low head and medium head turbines are classified based on ____________
a) Type of energy at inlet
b) Direction of flow through runner
c) Head at inlet of turbine
d) Specific speed of turbine
Answer: c
Explanation: Different heads of turbines classifies turbines based on their heads, namely Kaplan, Francis, Pelton.
5. Low specific speed, high specific speed and medium specific speed are classified based on ____________
a) Type of energy at inlet
b) Direction of flow through runner
c) Head at inlet of turbine
d) Specific speed of turbine
Answer: d
Explanation: Different specific speed of turbines classifies turbines based on their heads, namely Kaplan, Francis, Pelton.
6. If energy available at inlet of turbine is only kinetic energy then it is classified based on ____________
a) Type of energy at inlet
b) Direction of flow through runner
c) Head at inlet of turbine
d) Specific speed of turbine
Answer: a
Explanation: When there is energy such as kinetic energy at inlet, turbines is classified based on their energies at inlet. In this case, it is an impulse turbine.
7. If water flows in radial direction at inlet of runner and leaves axially at outlet then turbine is named as ____________
a) Tangential flow turbine
b) Axial flow turbine
c) Radial flow turbine
d) Mixed flow turbine
Answer: d
Explanation: In a mixed flow turbine, water enters in radial direction and exits axially.
8. Pelton turbine is operated under_________
a) Low head and high discharge
b) High head and low discharge
c) Medium head and high discharge
d) Medium head and medium discharge
Answer: b
Explanation: Based on heads and discharges, turbines are classified into Pelton, Francis or Kaplan. Pelton has high head and low discharge.
9. Kaplan turbine is operated under __________
a) Low head and high discharge
b) High head and low discharge
c) Medium head and high discharge
d) Medium head and medium discharge
Answer: a
Explanation: Based on heads and discharges, turbines are classified into Pelton, Francis or Kaplan. Kaplan has low head and high discharge.
10. Medium specific speed of turbine implies _____________
a) Pelton turbine
b) Kaplan turbine
c) Francis turbine
d) Propeller turbine
Answer: c
Explanation: Francis turbine is a widely used turbine. It has a medium specific speed.
11. High specific speed of turbine implies that it is ___________
a) Francis turbine
b) Propeller turbine
c) Pelton turbine
d) Kaplan turbine
Answer: d
Explanation: Kaplan turbines have high specific speeds compared to Francis and Pelton turbines.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Pelton Turbine Velocity Diagrams”.
1. Velocity triangles are used to analyze ____________
a) Flow of water along blades of turbine
b) Measure discharge of flow
c) Angle of deflection of jet
d) Flow of water, measure of discharge, angle of deflection
Answer: d
Explanation: By using velocity triangles we can determine discharge of flow, angle of deflection of jet and to measure relative velocity of jet with respect to speed of wheel.
2. In which of following turbine inlet and outlet blade velocities of vanes are equal?
a) Francis turbine
b) Kaplan turbine
c) Pelton turbine
d) Propeller turbine
Answer: c
Explanation: In Pelton turbine each blade has same angular velocity and same linear speed unlike Francis and Kaplan turbines.
3. Tangential velocity of blade of Pelton wheel is proportional to ____________
a) Speed of wheel
b) Angular velocity of wheel
c) Rpm of wheel
d) Speed, angular velocity, RPM of the wheel
Answer: a
Explanation: Usually velocity of blade is given by u=radius*angular velocity from which velocity is proportional to speed of wheel.
4. The value of coefficient of velocity is _____________
a) 0.98
b) 0.65
c) 0.85
d) 0.33
Answer: a
Explanation: Coefficient of velocity is defined as ratio of actual velocity of jet at vena contraction to theoretical velocity. Its value is approximate to 0.98.
5. In which of following turbine inlet whirl velocity and inlet jet velocity are equal in magnitude?
a) Pelton turbine
b) Propeller turbine
c) Kaplan turbine
d) Francis turbine
Answer: a
Explanation: In Pelton turbine velocity of inlet is parallel to splitter and is parallel to x axis which doesn’t have flow velocity.
6. In Pelton wheel, if outlet velocity angle of jet is “acute angled” then outlet whirl velocity of jet is ______________
a) x- component of V – blade velocity
b) x- component of V + blade velocity
c) Blade velocity – x- component of V
d) Zero
Answer: a
Explanation: By constructing velocity triangle we come to know that whirl velocity of jet is equal in magnitude to that of x- component of V r2 – blade velocity.
7. In Pelton wheel, if outlet velocity angle of jet is “obtuseangled” then outlet whirl velocity of jet is _____________
a) x- component of V – blade velocity
b) x- component of V + blade velocity
c) Blade velocity – x- component of V
d) Zero
Answer: c
Explanation:By constructing velocity triangle we come to know that whirl velocity of jet is equal in magnitude to that of Blade velocity – x- component of V .
8. In Pelton wheel, if outlet velocity angle of jet is “right angled” then outlet whirl velocity of jet is __________
a) x- component of V – blade velocity
b) x- component of V + blade velocity
c) Blade velocity – x- component of V
d) Zero
Answer: d
Explanation: By constructing velocity triangle we come to know that whirl velocity of jet is equal to zero as x- component of V= blade velocity.
9. In Pelton wheel, relative inlet velocity of jet with respect to velocity of vane is _____________
a) Difference between inlet jet velocity and blade velocity
b) Sum of inlet jet velocity and blade velocity
c) Inlet jet velocity
d) Blade velocity
Answer: a
Explanation: In Pelton turbine, inlet velocity of jet and velocity of vanes are in same direction and of different magnitude hence relative velocity is found by calculating its difference.
10. In Pelton wheel if angle of deflection is not mentioned then we assume it as______________
a) 150 degrees
b) 200 degrees
c) 165 degrees
d) 185 degrees
Answer: c
Explanation: It is standard value for deflection of jet, which is found by performing several experimental operations.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Work Done by Pelton Turbine”.
1. The work done per unit weight of water jet striking runner blades of Pelton turbine is given by expression ______________
a) [Vw1+Vw2] u/g
b) Vw1*u/g
c) [Vw1+Vw2]/g
d) [Vw1+Vw2]u
Answer: a
Explanation: Generally work done is force times velocity and expression for it is PQ [Vw1+Vw2] u/g and work done per unit weight gives [Vw1+Vw2]u/g.
2. In Pelton turbine the energy available at inlet of runner that is at outlet of nozzle is known as
a) Shaft power
b) Runner power
c) Output power
d) Water power
Answer: b
Explanation: In Pelton turbine the energy available at inlet of runner that is at outlet of nozzle is known as runner power, the energy available in penstock is water energy.
3. In Pelton turbines the expression for power delivered at inlet to runner is given by __________
a) W*[Vw1+Vw2]u/g
b) W*[Vw1-Vw2]u/g
c) W*[Vw1+Vw2]u/g, W*[Vw1-Vw2]u/g
d) [Vw1+Vw2]u/g
Answer: c
Explanation: Generally work done is force times velocity and expression for it is PQ [Vw1+Vw2] u/g and work done per unit weight gives [Vw1+Vw2]u/g.
4. In Pelton turbine runner power is more when compared with power available at exit of nozzle.
a) True
b) False
Answer: b
Explanation: Runner power is less when compared with power available at exit of nozzle due to frictional losses.
5. Kinetic energy of jet at inlet of turbine is given as __________________
a) 0.5*V1
b) 0.5*V1*V1
c) 0.5*V1*V1
d) 0.5*V1*V1
Answer: b
Explanation: Expression for kinetic energy is product of half times mass and square of velocity, mass can be written as density time volume.
Where, p = density of liquid, a = area of jet, V1 = inlet jet velocity
6. The force exerted by a jet of water in the direction of jet of jet on a stationary curved plates Fx is ____________
a) pav*v
b) pav
c) pav*v
d) pav*v
Answer: c
Explanation: Generally force is rate of change of momentum, in curved blade of angle k change of momentum will be pav*v .
Where, p=density, v=velocity of jet, k=blade angle.
7. The force exerted by a jet of water in the direction of jet of jet on moving curved plates is ___________
a) pa*
b) pa
c) pav*
d) pa*
Answer: c
Explanation: Generally force is rate of change of momentum, in curved blade of angle k change of momentum will bepav* here relative velocity is considered than absolute.
Where, p=density, v=velocity of jet, k=blade angle, u=blade velocity.
8. Calculate work done by jet per second on the runner where, discharge=0.7cubic meters/s, inlet and outlet whirl velocities be 23.77 and 2.94?
a) 200Kw
b) 150Kw
c) 187Kw
d) 250Kw
Answer: c
Explanation: As we know the expression for work done per second is W*[Vw1+Vw2] u/g on substituting the above given values we get it as 187Kw.
9. The power supplied at inlet of turbine in S.I units is known as_____________
a) Shaft power
b) Runner power
c) Water power
d) Total power
Answer: c
Explanation: The power supplied at inlet of turbine in S.I units is known as water energy, which contain both kinetic energy and pressure energy.
10.The expression for water power in Pelton wheel is ________________
a) Kw
b) Kw
c) Kw
d) Kw
Answer: a
Explanation: Expression for water power of Pelton turbine is potential energy of water which is converted into kinetic energy
can be written as Kw.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Efficiency of Pelton Turbines”.
1. The hydraulic efficiency of Pelton turbine will be maximum when blade velocity is equal to _______
a) V/2
b) V/3
c) V/4
d) V/5
Answer: a
Explanation: Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine. This efficiency will be maximum when differentiating it with “u” and it is obtained as u=v/2.
2. In Pelton turbine ___________ is defined as ratio between power delivered to runner and power supplied at inlet of turbine.
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: c
Explanation: Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine.
3. The maximum efficiency of Pelton turbine is _________
a) 80%
b) 70%
c) 50%
d) 88%
Answer: c
Explanation: We know that efficiency will be Maximumwhen blade velocity is equal to half of its jet velocity upon substitution we get efficiency as 50%.
4. In Pelton turbine product of mechanical efficiency and hydraulic efficiency is known as _____________
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: d
Explanation: Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency.
5. Among the following which turbine has least efficiency?
a) Pelton turbine
b) Kaplan turbine
c) Francis turbine
d) Propeller turbine
Answer: a
Explanation: Pelton is impulse turbine and remaining are reaction turbine, efficiency of reaction turbine is more compared to impulse turbine.
6. In Pelton ____________ is ratio of volume of water actually striking the runner and volume of water supplied to turbine.
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: b
Explanation: Volumetric efficiency is ratio between volume of water actually striking the runner of turbine and volume of water supplied to the turbine.
7. In Pelton turbine the ratio of volume available at shaft of turbine and power supplied at the inlet of the turbine is _______
a) Mechanical efficiency
b) Volumetric efficiency
c) Hydraulic efficiency
d) Overall efficiency
Answer: d
Explanation: Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency.
8. The expression for maximum hydraulic efficiency of Pelto turbine is given by ______________
a) /2 where k is outlet blade angle
b) /2 where k is outlet blade angle
c) /2 where k is outlet blade angle
d) /2 where k is outlet blade angle
Answer: a
Explanation: Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine. Its maximum value is obtained by replacing u=v/2 and it is /2 where k is outlet blade angle.
9. In the expression for overall efficiency of turbine, which is p/ , where “k” is known as _______
a) Specific density of liquid
b) Density of liquid
c) Specific gravity of liquid
d) Volume of liquid
Answer: b
Explanation: Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency. Its expression is given by p/ where k is density of liquid.
10. In Pelton turbine hydraulic efficiency is product of mechanical efficiency and overall efficiency.
a) True
b) False
Answer: b
Explanation: The above statement is false generally overall efficiency is product of mechanical and hydraulic efficiency.
11. The expression for hydraulic efficiency is given by
a) 2[1+cos k]u/V1*V1
b) 2[1+cos k]u/V1*V1
c) 2[1-cos k]u/V1*V1
d) 2[1+cos k]u/V1*V1
Answer: a
Explanation: Hydraulic efficiency is ratio of power delivered to runner to power supplied at inlet of turbine upon substituting the mathematical terms we get expression as follows.
Where, V1=inlet jet velocity, u=blade velocity, k=outlet blade angle
12. In Pelton turbine inlet velocity of jet is 85.83m/s, inlet and outlet whirl velocities be 85.83 and 0.143 and blade velocity be 38.62 then its hydraulic efficiency is ___________
a) 90.14%
b) 80%
c) 70%
d) 85%
Answer: a
Explanation: Substitute the above given values in expression for hydraulic efficiency which is given by expression 2[Vw1+Vw2] u/V1*V1 and we get it as 90.14%.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Design of Pelton Wheel”.
1. Design of Pelton wheel means the following data is to be determined.
a) Width of buckets
b) Depth of buckets
c) Number of buckets
d) All of the mentioned
Answer: d
Explanation: In design of Pelton wheel we determine diameter of jet, diameter of runner, Width of buckets, Depth of buckets, Number of buckets on runner.
2. The width of buckets of Pelton wheel is _________________
a) 2 times diameter of jet
b) 3 times diameter of jet
c) 4 times diameter of jet
d) 5 times diameter of jet
Answer: d
Explanation: To obtain Pelton wheel of higher efficiency, width of buckets is specified as 5 times diameter of jet by considering several experimental observations.
3. The depth of buckets of Pelton wheel ____________
a) 1.2 times diameter of jet
b) 1.3 times diameter of jet
c) 1.4 times diameter of jet
d) 1.5 times diameter of jet
Answer: a
Explanation: To obtain Pelton wheel of higher efficiency, depth of buckets is specified as 1.2 times diameter of jet by considering several experimental observations.
4. The ratio of pitch diameter of Pelton wheel to diameter of jet is known as ___________
a) Speed ratio
b) Jet ratio
c) Velocity ratio
d) Co-efficient of velocity
Answer: b
Explanation: The ratio of pitch diameter of Pelton wheel to diameter of jet is known as jet ratio.
5. Find the diameter of jet D, if jet ratio m and diameter of jet d are given as 10 and 125mm.
a) 1.25 meters
b) 1.5 meters
c) 2 meters
d) 1.2 meters
Answer: a
Explanation: Expression for jet ratio is m=D/d which is 10*0.125= 1.25 meters.
6. The number of buckets of Pelton wheel is 25 and diameter of runner is 1.5meters then calculate diameter of jet is ___________
a) 80mm
b) 85mm
c) 90mm
d) 82mm
Answer: b
Explanation: The expression for measuring number of buckets is 15 + diameter of runner/2 times diameter of jet by using this expression we get diameter of jet as 85mm.
7. In most of cases the value of jet ratio is _______________
a) 10
b) 11
c) 12
d) 13
Answer: c
Explanation: Jet ratio is 12 because in most of Pelton turbines diameter of runner is 12 times the diameter of jet.
8. Number of buckets on runner of Pelton wheel is given by expression?
a) 15 + D/2d
b) 15 + 3D/2d
c) 15 + D/d
d) 15 + 2D/d
Answer: a
Explanation: To obtain Pelton wheel of higher efficiency, number of buckets is specified as 15 + D/2d by considering several experimental observations.
9. ____________ is obtained by dividing total rate of flow through the turbine by rate of flow through single jet.
a) Number of jets
b) Diameter of jets
c) Velocity of jets
d) Speed ratio
Answer: a
Explanation: Total discharge is sum of individual discharges hence, by dividing total rate of flow through the turbine by rate of flow through single jet we get number of jets.
10. If diameter of jet is 85mm and diameter of runner is 1.5 meter then calculate width of buckets.
a) 400mm
b) 500mm
c) 420mm
d) 425mm
Answer: d
Explanation: The expression for measuring width of buckets is 5*diameter of jet, which is 5*85=425mm.
11. If diameter of jet is 85mm and diameter of runner is 1.5 meter then depth of buckets is ___________
a) 100mm
b) 105mm
c) 106mm
d) 102mm
Answer: d
Explanation: The expression for measuring depth of buckets is 1.2*diameter of jet, which is 1.2*85=102mm.
12. If diameter of jet is 85mm and diameter of runner is 1.5 meter then calculate number of buckets on Pelton wheel approximately
a) 20
b) 22
c) 23
d) 25
Answer: d
Explanation: The expression for measuring number of buckets is 15 + diameter of runner/2 time’s diameter of jet, which are 15 + 1.5/2*0.085.
13. The width of Pelton wheel should be 5 times the diameter of jet?
a) True
b) False
Answer: a
Explanation: To obtain Pelton wheel of higher efficiency, width of buckets is specified as 5 times diameter of jet by considering several experimental observations.
14. The ratio of diameter of jet to diameter of runner is _____________
a) 1:3
b) 1:6
c) 1:5
d) 3:4
Answer: b
Explanation: To obtain Pelton wheel of higher efficiency, diameter of runner is 5 times diameter of jet by considering several experimental observations.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Main Parts of Radial flow Reaction Turbines”.
1. Radial flow reaction turbines are those turbines in which water flows ____________
a) Radial direction
b) Axial direction
c) Tangential direction
d) All of the mentioned
Answer: a
Explanation: The name itself indicates the type of flow that is radial direction but the thing that is unknown is whether it is radially inward or outwards.
2. Main parts of radial flow reaction turbines are ______________
a) Casing
b) Guide mechanism
c) Draft tube
d) All of the mentioned
Answer: d
Explanation: The main parts in a radial turbine are tight casing to prevent spill of water, runner, guide vanes, guide mechanism to regulate flow and draft to increase inlet pressure.
3. Discharge through radial flow reaction turbine is ______________
a) P1*b1*Vf1
b) P2*b2*Vf2
c) P1*b2*Vf2
d) Both P1*b1*Vf1 & P2*b2*Vf2
Answer: d
Explanation: Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes.
Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=thickness and Vf=flow velocity.
4. Radial flow reaction turbines contain spiral casing which area ____________
a) Remains constant
b) Gradually decreases
c) Gradually increases
d) Suddenly decreases
Answer: b
Explanation: Area of spiral structure gradually decreases because as discharge decreases correspondingly area also decreases. So, runner will rotate with constant velocity.
5. ____________ consists of stationary circular wheel all around the runner of turbine
a) Casing
b) Guide mechanism
c) Runner
d) Drafting
Answer: b
Explanation: Guide vanes are placed around the runner to regulate the flow and to provide shock less entry at inlet to runner.
6. The casing of radial flow reaction turbine is made of spiral shape, so that water may enter the runner__________
a) Variable acceleration
b) Constant acceleration
c) Variable velocity
d) Constant velocity
Answer: d
Explanation: Area of spiral structure gradually decreases because as discharge decreases correspondingly area also decreases. So, runner will rotate with constant velocity.
7. _____________ allow the water to strike the vanes fixed on runner without shock at inlet
a) Casing
b) Guide vanes
c) Runner
d) Draft tube
Answer: b
Explanation: Guide vanes are placed around the runner to regulate the flow and to provide shock less entry at inlet to runner.
8. Runner blades are made up of _____________
a) Cast steel
b) Cast iron
c) Wrought iron
d) Steel
Answer: a
Explanation: Runner blades are made up of cast steel because they are less corrosive and highly durable.
9. The pressure at the exit of runner of reaction turbine is generally____________than atmospheric pressure
a) Greater
b) Lesser
c) Constant
d) Equal
Answer: b
Explanation: In general, the exit of runner has a low pressure compared to the atmospheric pressure.
10. ___________is a pipe of gradually increasing area used for discharging water from exit of the turbine to the tail race.
a) Casing
b) Guide mechanism
c) Draft tube
d) Runner
Answer: c
Explanation: Draft is a pipe of gradually increasing area, as water leaving runner has less pressure, draft tube will increase pressure energy of water by decreasing its velocity.
11. ____________and __________of radial flow reaction turbine are always full of water.
a) Casing and runner
b) Casing and penstocks
c) Runner and penstocks
d) Runner and draft tube
Answer: a
Explanation: Casing and runner are completely covered by water as it is a reaction turbine in which pressure energy is predominant.
12. ____________governs the flow of water entering the runner blades.
a) Casing
b) Guide vanes
c) Draft tube
d) Runner
Answer: b
Explanation: Guide vanes are placed around the runner to regulate the flow and to provide shock less entry at inlet to runner.
13. Spiral casing of reaction turbine will regulate the flow.
a) True
b) False
Answer: b
Explanation: Guide vanes are placed around the runner to regulate the flow and to provide shock less entry at inlet to runner.
This set of Hydraulic Machines test focuses on “Inward Radial Flow Reaction Turbines”.
1. Inward radial flow reaction turbine is a turbine in which water flows across the blades of runner______________
a) Radial direction
b) Radially inward
c) Radially outward
d) Axial direction
Answer: b
Explanation: The name itself indicates that flow is in radial direction and flowing from outer periphery towards center.
2. Which of following is inward radial flow reaction turbine?
a) Pelton wheel
b) Francis turbine
c) Axial turbine
d) Kaplan turbine
Answer: b
Explanation: Pelton is impulse a turbine, Kaplan is axial flow turbine and Francis is an inward flow reaction turbine.
3. In Inward radial flow reaction turbine which is not required?
a) Runner
b) Air tight casing
c) Guide vanes
d) Breaking jet
Answer: d
Explanation: Here in inward flow reaction turbine, instead of jet water is passed into spiral casing directly and breaking jet is not used for its halt instead of it guide vanes are used.
4. The main difference between reaction turbine and inward radial flow reaction turbine is water flows___________
a) Radial direction
b) Radially inward
c) Radially outward
d) Axial direction
Answer: b
Explanation: The name itself indicates the type of flow that is radial direction but the thing that is unknown is whether it is radially inward or outwards.
5. In Inward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as _______
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: b
Explanation: Flow ratio is known as ratio of tangential wheel at inlet to given velocity of jet and it is scalar quantity.
6. In Inward radial flow reaction turbine the ratio of tangential velocity at inlet to the given velocity ____________
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: a
Explanation: Speed ratio is ratio of tangential velocity at inlet to the given velocity and it is scalar quantity because it is ratio of two speeds.
7. The discharge through a reaction radial flow turbine is given by____________
a) P1*b1*Vf1
b) P2*b2*Vf2
c) P1*b2*Vf2
d) Both P1*b1*Vf1 & P2*b2*Vf2
Answer: d
Explanation: Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes.
Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=thickness and Vf=flow velocity
8. In Inward radial flow reaction turbine if thickness is considered then discharge is _________
a) *b1*Vf1
b) *b2*Vf2
c) *b2*Vf2
d) Both *b1*Vf1 & *b2*Vf2
Answer: d
Explanation: Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes. If n blades of thickness t is considered then discharge is *b1*Vf1.
Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=width, Vf=flow velocity, n=number of blades and t=thickness of blades
9. In Inward radial flow reaction turbine if angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at outlet is _____________
a) Radial inlet discharge
b) Radial outlet discharge
c) Flow ratio
d) Speed ratio
Answer: b
Explanation: If angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at outlet in radial flow reaction then total velocity will be flow velocity.
10. In which of following turbine whirl component is zero?
a) Reaction turbine
b) Inward radial flow reaction turbine
c) Axial flow turbine
d) Impulse turbine
Answer: b
Explanation: If angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at outlet in radial flow reaction turbines then total velocity will be flow velocity.
11. Discharge in inward flow reaction turbine ____________
a) Increases
b) Decreases
c) Remains constant
d) Gradually decreases
Answer: b
Explanation: Discharge in inward flow reaction turbine decreases because area decreases as fluid flows across spiral structure.
12. Speed control of Outward flow reaction turbine is _________
a) Easy
b) Moderate
c) Difficult
d) Very difficult
Answer: b
Explanation: In an outward reaction turbine, we can only partly control the speed.
13. Centrifugal head in inward flow reaction turbine __________
a) Increases
b) Decreases
c) Remains constant
d) Gradually decreases
Answer: b
Explanation: Because centrifugal head is proportional to difference of outlet blade velocity and inlet blade velocity.
Here, u2 < u1 so centrifugal head decreases.
14. Tendency of wheel to race is almost nil in ___________turbine.
a) Inward flow reaction turbine
b) Outward flow reaction turbine
c) Impulse turbine
d) Axial flow turbine
Answer: a
Explanation: In an inward reaction flow turbine, wheel moves with the constant speed.
15. Inward flow reaction turbine is used in practical applications.
a) True
b) False
Answer: a
Explanation: Inward flow reaction turbine is used in practical applications that is “Francis turbine”.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Degree of Reaction”.
1. The formation of vapour cavities is called _____
a) Static pressure drop
b) Cavitation
c) Isentropic expansion
d) Emulsion
Answer: b
Explanation: The formation of vapour cavities is called cavitation. It is formed due to the presence of small free liquids with different zones. These zones consists of different layers of forces acting on them.
2. What is the degree of reaction denoted as?
a) D
b) R
c) r
d) d
Answer: b
Explanation: Degree of reaction is defined as the ratio of the static pressure drop in the rotor to the static pressure drop in the stage. It can also be defined in the same way for enthalpy in different stages. It is denoted by the letter ‘R’.
3. Voids are created due to______
a) Reaction ratio
b) Pressure ratio
c) Liquid free layers
d) Volumetric layers
Answer: c
Explanation: Voids in a turbine or pump is created due to the presence of liquid free layers. It is formed due to the presence of small free liquids with different zones. These zones consists of different layers of forces acting on them.
4. Cavitation usually occurs due to the changes in ________
a) Pressure
b) Temperature
c) Volume
d) Heat
Answer: a
Explanation: Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
5. Degree of reactions are most commonly used in________
a) Turbomachinery
b) Pressure drag
c) Aerodynamics
d) Automobiles
Answer: a
Explanation: Degree of reaction is most commonly used in turbomachinery. Degree of reaction is defined as the ratio of the static pressure drop in the rotor to the static pressure drop in the stage. It can also be defined in the same way for enthalpy in different stages. It is denoted by the letter ‘R’.
6. At high pressure, the voids can generate ______
a) Drag force
b) Mass density
c) Shock waves
d) Flow speed
Answer: c
Explanation: At high pressure, the voids can generate shock waves. Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
7. Voids that implode near metal surface develops a_______
a) Drag force
b) Cyclic stress
c) Shock waves
d) Flow speed
Answer: b
Explanation: Voids that implode near metal surface develops a cyclic stress. This happens mainly due to repeated implosion of voids. Thus, option ‘b’ is correct.
8. In case of gas turbines and compressors, degree of reaction is ________
a) Static pressure drop in rotor/ static pressure drop in stage
b) Static pressure drop in stage/ static pressure drop in rotor
c) Isentropic enthalpy drop in rotor/ isentropic enthalpy drop in stage
d) Static temperature drop in stage/ static temperature drop in rotor
Answer: c
Explanation: Degree of reaction in terms of gas turbines and compressors is defined as the ratio of isentropic enthalpic drop that is developed in the rotor such as the moving blades to that of the isentropic heat drop in the fixed blades.
9. Non- inertial cavitation is the one in which a bubble of fluid is forced to oscillate.
a) True
b) False
Answer: a
Explanation: Non- inertial cavitation is the one in which a bubble of fluid is forced to oscillate. It oscillates in a different size or shape due to some form of energy called the acoustic field.
10. The efficiency of the vane is given by_________
a) 1-V 2 2 / V 1 2
b) 1-(V 2 2 / V 1 2 )
c) V 2 2 / V 1 2
d) 1- V 1 2
Answer: a
Explanation: In a velocity triangle at the inlet and the outlet, the control volume is moving with a uniform velocity. Therefore, the momentum theorem of the control volume is at a steady flow. Thus, the efficiency of the vane is given by 1-(V 2 2 / V 1 2 ).
11. The velocities of the blade angles can be found out using________
a) Mach number
b) Froude’s number
c) Velocity triangles
d) Reynolds number
Answer: c
Explanation: The velocity triangle represents various components. It mainly determines the velocities of fluids that act in a turbomachinery. It can be drawn for both inlet and outlet triangles with its angles.
12. Which among the following velocities cannot be found using the velocity triangle?
a) Tangential
b) Whirl
c) Relative
d) Parabolic
Answer: d
Explanation: The velocity triangle represents various components. It mainly determines the velocities of fluids that act in a turbomachinery. It can be drawn for both inlet and outlet triangles with its angles.
13. Hydrodynamic cavitation is due to the process of _________
a) Vaporisation
b) Sedimentation
c) Filtration
d) Excavation
Answer: a
Explanation: Hydrodynamic cavitation is due to the process of vaporisation. A bubble generation takes place in which implosion occurs during the flowing of liquid.
14. The process of bubble generation leads to __________
a) High temperatures
b) High pressures
c) High energy densities
d) High volumetric ratio
Answer: c
Explanation: The process of bubble generation leads to high energy densities. The local temperatures and local pressures at this point last for a very short time. Thus, the option is ‘c’.
15. Super cavitation is the use of cavitation effect to create a bubble of steam inside a liquid.
a) True
b) False
Answer: a
Explanation: Yes, it is true. Super cavitation is the use of cavitation effect to create a bubble of steam inside a liquid. It is large to encompass an object passing through the liquid to reduce skin friction drag.
16. Degree of reaction turbine is the ratio of?
a) Pressure energy to total energy
b) Kinetic energy to total energy
c) Potential energy to total energy
d) Kinetic energy to potential energy
Answer: a
Explanation: Degree of reaction is defined to be the ratio of pressure and total energies inside the runner of a turbine.
17. Which of these options are best suited for the total energy change inside the runner per unit weight?
a) Degree of action
b) Degree of reaction
c) Turbulence
d) Efficiency of turbine
Answer: b
Explanation: Degree of reaction is defined to be the ratio of pressure and total energies inside the runner of a turbine.
18. Which of these ratios are termed to be hydraulic efficiency?
a) Water power to delivered power
b) Delivered power to input power
c) Power lost to power delivered
d) Runner power to water power
Answer: d
Explanation: From the equation of hydrodynamic machines, we get hydraulic efficiency to be the ratio of runner power and water power.
19. When a container containing a liquid is rotated, then due to centrifugal action, then which of these energies are changed?
a) Kinetic energy
b) Pressure energy
c) Potential energy
d) Energy due to viscous force
Answer: b
Explanation: When a container containing a liquid is rotated, then due to centrifugal action there is a change in pressure energy.
20. For an actual reaction turbine, what should be the angle beta, such that the loss of kinetic energy at the outlet is to be minimum?
a) 90
b) 45
c) 60
d) 30
Answer: a
Explanation: Only when the angle beta is 90, V2 will be minimum so that loss of kinetic energy is minimized.
21. Discharge through a reaction flow reaction turbine is given by, Q = ______
a) Pi*d*b*Vf1
b) Pi*d*d*b*Vf1
c) Pi*d*b*b*Vf2
d) Pi*b*b*Vf1
Answer: a
Explanation: The discharge in a radial flow reaction turbine is the product of diameter, width and velocity of flow at inlet Vf1 with pi.
22. When the thicknesses of vanes are to be considered in the discharge of a turbine, what will be the area under consideration?
a) Pi*d – n*t
b) Pi*d – n*n*t
c) Pi*d – t*t
d) Pi*d *d– n*t
Answer: a
Explanation: When the thicknesses of vanes are to be considered in the discharge of a turbine, and n is the number of vanes, are is given by Pi*d – n*t.
23. The speed ratio is defined as u/ 1/2
a) True
b) False
Answer: a
Explanation: The speed ratio is termed to be the ratio of tangential velocity at inlet to square root of 2gH.
24. Flow ratio is defined as Vf1/ 1/2
a) False
b) True
Answer: b
Explanation: Flow ratio is the ratio between velocities of flow at inlet to square root of 2gH. Here, H is the head of the turbine.
25. _________ means the angle made by absolute velocity with the tangent on the wheel is 90 degrees and the component of whirl velocity is zero.
a) Axial discharge
b) Tangential discharge
c) Turbulent discharge
d) Radial discharge
Answer: d
Explanation: Radial discharge is the angle made by absolute velocity with the tangent on the wheel is 90 degrees and the component of whirl velocity is zero. Radial discharge at outlet means the angle beta is 90.
26. In a Francis turbine, degree of reaction lies between _____
a) 0 and 1
b) 1 and 2
c) 0 and 0.5
d) 0.5 and 0.1
Answer: a
Explanation: For a Francis turbine, theoretically and practically, 0< R< 1.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Outward Radial Flow Reaction Turbines – 1”.
1. In an outward flow reaction turbine, water from casing enters guiding wheel.
a) True
b) False
Answer: a
Explanation: Water enters the stationary guide wheel from the casing of the turbine in the outward radial flow reaction turbine.
2. The water from penstocks enters the _____ which is spiral in shape which the area of cross section of casing goes on decreasing gradually
a) guide wheel
b) draft tube
c) casing
d) runner
Answer: c
Explanation: The water from penstocks enters the casing which is spiral in shape in which the area of cross section of casing decreases gradually.
3. If the water flows from inwards to outwards, the turbine is known as _____________
a) Tangential flow turbine
b) Turbulent low inward flow
c) Inward flow turbine
d) Outward flow turbine
Answer: d
Explanation: If the water in the runner flows from inwards to outwards, then such type of turbine is said to be outward radial flow turbine.
4. In general, reaction turbines consist of which types of energies?
a) kinetic energy and potential energy
b) potential energy and pressure energy
c) kinetic energy and pressure energy
d) gravitational energy and potential energy
Answer: c
Explanation: Reaction turbine is a kind of turbine in which the water at inlet of the turbine possesses both kinetic energy and pressure energy.
5. ___________ is a circular wheel on which a series of smooth, radial curved vanes are fixed.
a) Guide wheel
b) Runner
c) Casing
d) Draft tube
Answer: b
Explanation: The radial curved vanes are so shaped that water enters and leaves the runner without shock .It is a circular type wheel on which a series of smooth, radial curved vanes are fixed.
6. In outward radial flow reaction turbines, tangential velocity at inlet is less than that of the outlet.
a) False
b) True
Answer: b
Explanation: In outward radial flow reaction turbines, tangential velocity at inlet is less than that of the outlet as the inlet of the runner is the inner diameter.
7. In an outward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as ___________
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: b
Explanation: Flow ratio is known as ratio of tangential wheel at inlet to given velocity of jet and it is scalar quantity.
8. In an outward radial flow reaction turbine the ratio of tangential velocity at inlet to the given velocity is ______
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: a
Explanation: Speed ratio is ratio of tangential velocity at inlet to the given velocity and it is scalar quantity because it is ratio of two speeds.
9. Discharge in an outward flow reaction turbine ____________
a) Increases
b) Decreases
c) Remains constant
d) Gradually decreases
Answer: a
Explanation: Discharge in an outward flow reaction turbine increases because area increases as fluid flows across spiral structure in the turbine.
10. An outward radial reaction turbine has ______
a) u1 < u2
b) u1 > u2
c) u1 = u2
d) u2 = u1 = 0
Answer: a
Explanation: For an outward flow reaction turbine, tangential velocity at inlet should be less than the tangential velocity at outlet.
11. An outward flow reaction turbine, ________
a) D1 > D2
b) D1 < D2
c) D1 = D2
d) D1 = D2 = 0
Answer: b
Explanation: In an outward flow reaction turbine, to maintain flow of water, the inlet diameter should be less than outlet diameter.
12. ___________is ratio of pressure energy change inside runner to total energy change inside runner
a) Degree of reaction
b) Speed ratio
c) Flow ratio
d) Hydraulic efficiency
Answer: a
Explanation: This is just a formula and it is scalar quantity because it is ratio of two changes of energies.
13. Degree of reaction for impulse turbine
a) 0
b) 1
c) 2
d) 3
Answer: a
Explanation: For pelton turbine u1=u2 and Vr1=Vr2 by substituting these values in degree of reaction we get it as 0.
14. The formula for degree of reaction for hydraulic turbines is __________
a) 1- /**
b) / **
c) 1+ / **
d) 1- / **
Answer: a
Explanation: This is obtained by substituting mathematical terms in actual expression of degree of reaction.
Where, V=jet velocity, Vr=relative velocity, u=blade velocity
15. Degree of reaction for reaction turbine is _____________
a) 1- cot x /2
b) 1+ cot x /2
c) 1- cot x /2
d) 1+ cot x /2
Answer: a
Explanation: Because for reaction turbine Vw2=0 and V2=Vf2, there is also no much change in velocity of flow implies that Vf1=Vf2 by substituting these values, we get it.
16. A turbine is a ________
a) Rotary mechanical device
b) Static pressure drop device
c) Electrical device
d) Static temperature device
Answer: a
Explanation: Turbine is a vortex related device. It means turbulence. Turbine is a rotary mechanical device. The energy generated from the turbine can be used to generate electrical power. It is used in jet engines.
17. Turbine converts _________
a) Work to energy
b) Energy to work
c) Work to Electricity
d) Work to pressure
Answer: b
Explanation: Turbine extracts energy and converts it into useful work. Turbine is a vortex related device. It means turbulence. Turbine is a rotary mechanical device. The energy generated from the turbine can be used to generate electrical power. It is used in jet engines.
18. Turbine extracts energy from________
a) Reaction ratio
b) Pressure ratio
c) Fluid flow
d) Volumetric ratio
Answer: c
Explanation: Turbine extracts energy from fluid flow and converts it into useful work. Turbine is a vortex related device. It means turbulence. Turbine is a rotary mechanical device. The energy generated from the turbine can be used to generate electrical power. It is used in jet engines.
19. Inward flow reaction turbine enter through ______
a) Outer periphery
b) Blades
c) Inner periphery
d) Pressure angle
Answer: a
Explanation: Inward flow flow reaction turbine enter through outer periphery of the turbine. It provides a force at the outer curvature of the blades to provide an inward flow.
20. A turbine is a ________
a) Turbomachinery
b) Pressure drag
c) Aerodynamics
d) Automobiles
Answer: a
Explanation: A turbine is a turbomachinery. Turbine extracts energy from fluid flow and converts it into useful work. Turbine is a vortex related device. It means turbulence. Turbine is a rotary mechanical device.
21. Centrifugal flow is imparted when the__________
a) Reaction flow is negative
b) Reaction flow is positive
c) Efficiency is 100 percent
d) Reaction rate is negligible
Answer: c
Explanation: Centrifugal flow is imparted when the reaction flow is negative in its direction. This happens when the centrifugal head loses its relative velocity with the flow of water.
22. Where is the turbine not used?
a) Solar power
b) Windmill
c) Water wheels
d) Gas plant
Answer: a
Explanation: Turbine is not used in solar power plants. The source of energy in solar power plants is the sunlight. It falls on the solar plates during the day, which stores the energy and converts them into useful work.
23. In an inward flow reaction turbine the discharge _______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: In an inward flow reaction turbine the discharge of fluid decreases. Thus, making it different from an outward flow reaction turbine.
24. A working fluid contains kinetic energy only.
a) True
b) False
Answer: b
Explanation: A working fluid contains kinetic energy and potential energy. The fluid that flows and hits the turbine blades coverts kinetic energy into useful work. The flow can be either compressible or incompressible.
25. In impulse turbines with moving blades, there is no _________ in blades of the turbine.
a) Pressure change
b) Same pressure
c) Volumetric change
d) Pressure independent
Answer: a
Explanation: In impulse turbines, there is no pressure change in blades of the turbine. There is no pressure change that is developed in fluid or gas in the turbine blades. The turbine blades are in moving condition.
26. In impulse turbines with stationary blades, there is_________ in blades of the turbine.
a) Pressure change
b) Same pressure
c) Volumetric change
d) Pressure independent
Answer: a
Explanation: In impulse turbines, there is pressure change in blades of the turbine. There is pressure change that is developed in fluid or gas in the turbine blades. The turbine blades are in stationary condition.
27. In an outward flow reaction turbine the discharge _______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: a
Explanation: In an outward flow reaction turbine the discharge of fluid increases. Thus, making it different from an inward flow reaction turbine.
28. Before reaching the turbine, the acceleration of the fluid takes place through the__________
a) Vane angle
b) Nozzle
c) Pump
d) Pipe
Answer: b
Explanation: Before the fluid reaches the turbine, the pressure head is converted into its velocity head by accelerating the fluid with a nozzle. Nozzle increases the velocity and decreases the pressure.
29. The Pelton wheel extracts energy from________
a) Vane angle
b) Moving fluid
c) Increase in temperature
d) Heat rejection
Answer: b
Explanation: The Pelton wheel extracts energy from moving of fluid. When the fluid flows through the Pelton wheel, a kinetic energy is developed. This kinetic energy is extracted from the moving fluid.
30. Pelton wheel is a Reaction type water turbine.
a) True
b) False
Answer: b
Explanation: The statement is false. The Pelton wheel is not a reaction type water turbine. It is an impulse type water turbine. The Pelton wheel extracts energy from moving of fluid. When the fluid flows through the Pelton wheel, a kinetic energy is developed.
This set of Hydraulic Machines Interview Questions and Answers for freshers focuses on “Outward Radial Flow Reaction Turbines – 2”.
1. The outward radial flow reaction turbine is a turbine in which direction of water flow is ___________
a) Radial direction
b) Radially inward
c) Radially outward
d) Axial direction
Answer: c
Explanation: The name itself indicates that flow is in radial direction and flowing from center towards outer periphery.
2. Outward flow reaction turbine is used in practical applications
a) True
b) False
Answer: b
Explanation: There are several limitations of outward flow reaction turbine hence it is used in practical applications.
3. The energy available at inlet for outward reaction flow turbine is ____________
a) Potential
b) Kinetic energy
c) Pressure energy
d) Pressure energy and Kinetic energy
Answer: d
Explanation: Since it is reaction turbine energy available at inlet consists of both pressure energy and kinetic energy.
4. Centrifugal head in Outward flow reaction turbine _____________
a) Increases
b) Decreases
c) Remains constant
d) Gradually decreases
Answer: a
Explanation: Because centrifugal head is proportional to difference of outlet blade velocity and inlet blade velocity .
Here, u1<u2 so centrifugal head increases.
5. Discharge in outward flow reaction turbine ____________
a) Increases
b) Decreases
c) Remains constant
d) Gradually decreases
Answer: a
Explanation: Discharge in outward flow reaction turbine increase because area increases to keep velocity constant.
6. Speed control of Outward flow reaction turbine is _____________
a) Easy
b) Moderate
c) Difficult
d) Very difficult
Answer: d
Explanation: None.
7. Tendency of wheel to race is predominant in____________turbine
a) Inward flow reaction turbine
b) Outward flow reaction turbine
c) Impulse turbine
d) Axial flow turbine
Answer: b
Explanation: None.
8. Outward flow reaction turbine will quite suitable for_____________
a) High head
b) Medium head
c) Low head
d) Static head
Answer: b
Explanation: Since it is radial flow reaction turbine which is operated under medium head and medium discharge.
9. In outward flow reaction turbine tangential velocity at inlet is always__________than outlet velocity.
a) Equal
b) Less
c) More
d) Constant
Answer: b
Explanation: Though runner has same angular velocity, diameter of outer periphery is large when compared to inner diameter.
10. In outward radial flow reaction turbine if angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at inlet is _______________
a) Radial inlet discharge
b) Radial outlet discharge
c) Flow ratio
d) Speed ratio
Answer: a
Explanation: if angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at inlet in radial flow reaction then total velocity will be flow velocity.
11. In outward radial flow reaction turbine if thickness is considered then discharge is ____________
a) *b1*Vf1
b) *b2*Vf2
c) *b2*Vf2
d) Both *b1*Vf1 & *b2*Vf2
Answer: d
Explanation: Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes. If n blades of thickness t is considered then discharge is *b1*Vf1.
Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=width, Vf=flow velocity, n=number of blades and t=thickness of blades.
12. The main difference between reaction turbine and outward radial flow reaction turbine is water flows __________
a) Radial direction
b) Radially inward
c) Radially outward
d) Axial direction
Answer: b
Explanation: The name itself indicates the type of flow that is radial direction but the thing that is unknown is whether it is radially inward or outwards.
13. In outward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as ___________
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: b
Explanation: Flow ratio is known as ratio of tangential wheel at inlet to given velocity of jet and it is scalar quantity.
14. Conical diffuser draft tube is also called_______
a) Straight divergent tube
b) Simple elbow tube
c) Thermal tube
d) Elbow tube with varying cross section
Answer: a
Explanation: Conical diffuser draft tube is one of the most commonly used drafts tubes in the Kaplan turbine. It works as an outlet at the Kaplan turbine. Conical diffuser draft tube is also called straight divergent tube.
15. Steam turbine converts energy into________
a) Electrical work
b) Mechanical work
c) Chemical work
d) Thermal work
Answer: b
Explanation: Turbine extracts energy and converts it into useful work. Turbine is a vortex related device. It means turbulence. Steam turbine converts energy into mechanical work by extracting thermal energy from pressurized steam.
16. Most common application of steam turbine is _______
a) Motor
b) Generator
c) Pump
d) Filter
Answer: b
Explanation: Since the turbine generates rotary motion, it is best suited for the use of electrical generator. It is used to drive an electrical generator. Now a days, the maximum usage for generation of electricity is done by using an electrical generator.
17. Conical diffuser draft tube consists of conical diffuser with angles of______
a) 10 degrees
b) 20 degrees
c) 30 degrees
d) 40 degrees
Answer: a
Explanation: Conical diffuser draft tube is one of the most commonly used drafts tubes in the Kaplan turbine. Conical diffuser draft tube consists of conical diffuser with angles less than or equal to 10 degrees.
18. What is the purpose of a conical diffuser?
a) To prevent flow separation
b) To avoid Pressure drag
c) To prevent rejection of heat
d) To increase efficiency
Answer: a
Explanation: Conical diffuser draft tube is one of the most commonly used drafts tubes in the Kaplan turbine. It is called so because it consists of a conical diffuser. The main function of the diffuser is to prevent flow separation.
19. What is the efficiency of conical diffuser draft tube?
a) 30
b) 50
c) 70
d) 90
Answer: d
Explanation: Conical diffuser draft tube is one of the most commonly used drafts tubes in the Kaplan turbine. It is called so because it consists of a conical diffuser. The main function of the diffuser is to prevent flow separation. The efficiency of conical diffuser draft tube is 90 percent.
20. The simple elbow draft tube is placed close to the_______
a) Head race
b) Tail race
c) Tank
d) Nozzle
Answer: b
Explanation: The simple elbow draft tube is placed close to the tail race. It consists of an extended elbow type tube. It is mainly used in the Kaplan turbine. It is placed close to the tail race of the turbine.
21. Turbine that consists of moving nozzles and with fixed nozzles is called as__________
a) Impulse turbine
b) Curtis turbine
c) Rateau turbine
d) Reaction turbine
Answer: d
Explanation: A turbine that consists of moving nozzles which are alternating with the fixed nozzles is called as a reaction turbine. When the steam hits the nozzle, the pressure is decreased and the temperature is increased.
22. An example of reaction turbine is________
a) Parsons turbine
b) Curtis turbine
c) Rateau turbine
d) Pelton wheel
Answer: a
Explanation: A turbine that consists of moving nozzles which are alternating with the fixed nozzles is called as a reaction turbine. When the steam hits the nozzle, the pressure is decreased and the temperature is increased. It is also called as Parson’s turbine.
23. When we arrange turbine blades in multiple stages it is called ________
a) Pressure change
b) Vane deviation
c) Compounding
d) Pressure ratio
Answer: c
Explanation: When we arrange turbine blades in multiple stages it is called as compounding. Compounding plays an essential role in turbines. It has various plus points.
24. Compounding is needed to ___________
a) Increase Pressure
b) Decrease temperature
c) Change volume
d) Increase efficiency
Answer: d
Explanation: Compounding is needed to improve efficiencies at low speeds. When we arrange turbine blades in multiple stages it is called as compounding. Compounding plays an essential role in turbines.
25. Which among the following is not a type of compounding?
a) Pressure
b) Temperature
c) Pressure velocity
d) Velocity
Answer: b
Explanation: Temperature is not a type of compounding. The three important types of compounding are pressure compounding, velocity compounding and pressure- velocity compounding.
26. Newtons second law describes the transfer of energy through impulse turbines.
a) True
b) False
Answer: a
Explanation: Before the fluid reaches the turbine, the pressure head is converted into its velocity head by accelerating the fluid with a nozzle. Thus, Newtons second law describes the transfer of energy through impulse turbines.
27. Inner radial flow extracts energy from _____
a) Turbine blades
b) Moving fluid
c) Pressure change
d) Temperature increase
Answer: b
Explanation: Inner radial flow extracts energy from moving fluid of a turbine. It also helps in determine the efficiency of the turbine blades.
28. Reaction turbines develop torque by reacting to the gas or fluids pressure or mass.
a) True
b) False
Answer: a
Explanation: Reaction turbines develop torque by reacting to the gas or fluids pressure or mass. The pressure or the gas of a fluid changes during this as it contains the working fluid acts on the turbine stages.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Francis Turbine Velocity Diagrams”.
1. What is the water flow direction in the runner in a Francis turbine?
a) Axial and then tangential
b) Tangential and then axial
c) Radial and then axial
d) Axial and then radial
Answer: c
Explanation: Francis turbine is radial flow reaction turbine. Though the water enters the turbine tangentially, it enters the runner radially inward and flows outward along the axis of the runner.
2. Which of the following is true in case of flow of water before it enters the runner of a Francis Turbine?
a) Available head is entirely converted to velocity head
b) Available head is entire converted to pressure head
c) Available head is neither converted to pressure head nor velocity head
d) Available head is partly converted to pressure head and partly to velocity head
Answer: d
Explanation: Since Francis Turbine is a reaction turbine, part of the available head is converted to velocity head. It is not entirely converted to velocity head. The rest of the available head is converted into pressure head.
3. Why does the cross sectional area of the Spiral casing gradually decrease along the circumference of the Francis turbine from the entrance to the tip?
a) To ensure constant velocity of water during runner entry
b) To prevent loss of efficiency of the turbine due to impulsive forces caused by extra area
c) To prevent leakage from the turbine
d) To reduce material costs in order to make the turbine more economical
Answer: a
Explanation: The primary purpose of the gradual decrease in area is so that the runner sees constant velocity of water at each point of entry. Absence of this may lead to inefficiency. The spiral casing is used to prevent leakage from the turbine but the gradual decrease in area is not for that reason.
4. Which of the following profiles are used for guide vanes to ensure smooth flow without separation?
a) Rectangular
b) Bent Rectangular
c) Elliptical
d) Aerofoil
Answer: d
Explanation: Smooth flow and flow without separation can be ensured when the cross sectional profile of the guide vanes are aerofoil in nature. Aerofoil shape is used in airplane wings to ensure smooth flow too. Rectangular profiles are not effective in guiding the water into the runner. Elliptical profiles will cause more drag, finally ending up with turbine inefficiency.
5. In which of the following type of runners the velocity of whirl at inlet is greater than the blade velocity?
a) Such a case is practically impossible
b) Slow Runner
c) Medium Runner
d) Fast Runner
Answer: b
Explanation: Considering the velocity diagram of Francis turbine at the inlet for a slow runner, we notice that the whirl velocity exceeds the blade velocity along the same direction. They are equal in case of a medium runner.
6. Which of the following runner types will have the highest vane angle at inlet ?
a) Slow Runner
b) Medium Runner
c) Fast Runner
d) Vane angle is defined only for Kaplan Turbines and not Francis turbines
Answer: c
Explanation: Considering the velocity diagram of Francis turbine at the inlet for a fast runner, vane angle is an obtuse angle. Whereas, it is right angle for medium runner and an acute angle for a slow runner.
7. In case of a Medium runner, tan CANNOT be given by ?
a) V f1 / V w1
b) V r1 / V w1
c) V r1 / u 1
d) V w1 / u 1
Answer: d
Explanation: In medium runner, V f1 = V r1 & V w1 = u 1 . V w1 and u 1 are along the same direction, hence that cannot be written as tan .
8. In the velocity diagrams for Francis turbine, which of the following velocity directions is along the blade curvature?
a) V r1
b) V w1
c) V 1
d) u 1
Answer: a
Explanation: V r1 is the relative velocity of the water flow as seen from the blade. Thus, relative velocity is along the direction of the curvature of the blade.
9. In the figure shown below,which of the following angles replace the question mark?
hydraulic-machines-questions-answers-velocity-diagrams-q9
a) Guide vane angle at inlet
b) Blade angle at inlet
c) Vane angle at inlet
d) Blade angle at outlet
Answer: a
Explanation: The angle between V 1 and the blade velocity u 1 is α1, which is the guide vane angle at the inlet.
10. In the figure shown below, which of the following type of runners has the blade curvature as shown in the above figure ?
hydraulic-machines-questions-answers-velocity-diagram-q10
a) Information insufficient to determine
b) Slow Runner
c) Medium Runner
d) Fast Runner
Answer: b
Explanation: Fast runners have forward curved blades, where slow runners have backward curved blades. The blades shown in the figure are backward curved blades of a runner, which are used for slow runners.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Workdone by Francis Turbine”.
1. Francis turbine is typically used for which of the following values of available heads?
a) 300 m
b) 100 m
c) 30 m
d) 5 m
Answer: b
Explanation: Francis Turbine is a medium head turbine, typically used for heads in the range 60 m to 240 m. Hence, only 100 m from the above options fit in that range.
2. Water flow velocity is given 10 m/s. The runner diameter is 3 m and the width of the wheel is 25 cm. Find the mass of water flowing across the runner per second.
a) 7500π
b) 50π
c) 300π
d) RPM of the turbine needs to be given
Answer: a
Explanation: Area of the flow = πDB = 0.75π m2. Mass flow rate = ρ.A.Vf = 1000*0.75π*10 = 7500π kg/s.
3. Work done per second by a Francis turbine can be given by ρAVf .
a) True
b) False
Answer: b
Explanation: The work done per second is given by ρAVf . Hence, the outlet term is subtracted from the inlet term and not added to it.
4. Which of the following terms is considered to be zero while deriving the equation for work done per second for Francis Turbine?
a) V r1
b) V w2
c) V f2
d) V r2
Answer: b
Explanation: Since the flow out of the runner of the Francis turbine is axial in nature, the whirl velocity at outlet is zero. Hence, V w2 is ignored in the derivation of work done for Francis Turbine.
5. Power developed by Francis turbine are calculated for a certain set of conditions. Now, the inlet whirl velocity is doubled, the blade velocity at inlet is doubled and the flow velocity is quartered. The power developed:
a) Is 4 times the original value
b) Is 2 times the original value
c) Is ½ times the original value
d) Is same as the original value
Answer: d
Explanation: The power developed by a Francis Turbine is given by P = ρAV . Hence, if inlet whirl velocity is doubled, the blade velocity at inlet is doubled and the flow velocity is quartered, then the power developed will remain the same as its original value.
6. Volume flow rate of water in a Francis turbine runner is 25 m3/s. The flow velocity, whirl velocity and blade velocity are 11 m/s, 10 m/s and 5 m/s respectively, all values given at runner inlet. Find the power developed by the turbine.
a) 25 kW
b) 1.25 MW
c) 1.25 kW
d) 25 MW
Answer: b
Explanation: P = ρQ (V w1 .u 1te is directly given.
7. The flow rate of the water flow in a Francis turbine is increased by 50% keeping all the other parameters same. The work done by the turbine changes by?
a) 50% increase
b) 25% increase
c) 100% increase
d) 150% increase
Answer: a
Explanation: The Power developed in a Francis turbine directly depends on the flow rate of water. If flow rate is increased by 50%, i.e. made 1.5 times the original value, then the power developed becomes 1.5 times its original value too. Hence, a 50% increase.
8. A student performs an experiment with a Francis turbine. He accidently set the RPM of Francis turbine to 1400 rpm instead of 700 rpm. He reported the power to be 1 MW. His teacher asks him to perform the same experiment using the correct RPM. The student performs the same experiment again, but this time the erroneously doubled the flow velocity. What does the student report the power to be?
a) 0.5 MW
b) 0.25 MW
c) 2 MW
d) 1 MW
Answer: d
Explanation: The Power developed by the turbine varies directly with both flow velocity as well as the blade velocity . So, if all parameters were correct, the reported value should be 0.5 MW. But, flow velocity is again doubled, so the student again reports 1 MW.
9. Velocity of whirl at the runner inlet is given to be 10 m/s and blade velocity to be 5 m/s. The volume flow rate of water in Francis turbine is given to be 25 m 3 /s. Find the power generated by the turbine?
a) 1700 HP
b) 800 HP
c) 3400 HP
d) 1000 HP
Answer: a
Explanation: P = ρQ (V w1 .u 1 ) = 1.25 MW. It is important to know the 1 HP = 736 W. Hence, the answer is 1.25 MW/ 736 = 1700 HP.
10. The available head of a Francis Turbine is 100 m. Velocity of the flow at the runner inlet is 15 m/s. Find the flow ratio.
a) 0.33
b) 0.45
c) 0.67
d) 0.89
Answer: a
Explanation: Flow ratio is given by ψ = Vf1 / sqrt. Substituting the given values and taking the value of g = 10 m/s 2 , we get ψ = 0.33.
11. How does the flow ratio of a Francis turbine vary with available head ?
a) ψ α H
b) ψ α 1/H
c) ψ α sqrt
d) ψ α 1/)
Answer: d
Explanation: Flow ratio is given by ψ = Vf1 / sqrt. Hence, the flow ratio is inversely proportional to the square root of available head.
12. What is the typical value for flow ratio in a Francis turbine?
a) 0.05 – 0.1
b) 0.15 – 0.30
c) 0.35 – 0.45
d) 0.50 – 0.60
Answer: b
Explanation: Flow ratio denoted by ψ is given by Vf1 / sqrt. Sqrt is called the spouting velocity. The practical values of the flow ratio for Francis turbine lie in the range of 0.15 – 0.3.
13. The available head of a Francis Turbine is 120 m. The blade velocity is given 35 m/s. Find the speed ratio of the turbine.
a) 0.56
b) 0.61
c) 0.71
d) 0.81
Answer: c
Explanation: The speed ratio φ = U/ sqrt. Hence, substituting the given values into this equation, we get φ = 0.71.
14. The speed ratio varies directly with which of the following parameters?
a) Vw1
b) V1
c) N
d) H
Answer: c
Explanation: The speed ratio is given by φ = U/ sqrt. Speed ratio directly depends upon U which in turn depends directly upon RPM of the turbine .
15. The typical value range of speed ratio for a Francis turbine is:
a) 0.3 – 0.6
b) 0.5 – 0.6
c) 0.1 – 0.4
d) 0.6 – 0.9
Answer: d
Explanation: Speed ratio denoted by φ is given by U / sqrt. Sqrt is called the spouting velocity. The practical values of the speed ratio for Francis turbine lie in the range of 0.6 – 0.9.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Efficiency of Francis Turbine”.
1. Which of the following efficiencies for Francis Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: a
Explanation: The definition of Hydraulic efficiency in a Francis turbine states that it is the ratio between the Runner power to the shaft power. Hence, the correct option is Hydraulic efficiency.
2. Which of the following efficiencies for Francis Turbine is described as the ratio between total quantity of water over runner blades to total quantity of water supplied to turbine?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: b
Explanation: The definition of volumetric efficiency in a Francis turbine states that it is the ratio between the total volume of water flowing over the runner blades to the volume of water entering the turbine. Hence, the correct option is volumetric efficiency.
3. Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft of the turbine to the power produced by the runner?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: c
Explanation: The definition of Mechanical efficiency in a Francis turbine states that it is the ratio between the Shaft power to the Runner power. Hence, the correct option is Mechanical efficiency.
4. Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: d
Explanation: The definition of Overall efficiency in a Francis turbine states that it is the ratio between the Shaft power to the Water power. Hence, the correct option is Overall efficiency.
5. The whirl velocity at inlet of Francis turbine is given to be 20 m/s. The blade velocity is given as 35 m/s. What is the hydraulic efficiency for a head of 100 m?
a) 80%
b) 90%
c) 70%
d) 98%
Answer: c
Explanation: The hydraulic efficiency of a Francis turbine is given by ηh = Vw1.u1/ gH. Substituting the values of the given parameters in the equation, we get hydraulic efficiency = 70%.
6. The desired hydraulic efficiency of a turbine is 80% at a whirl velocity of 20 m/s and a head of 100 m. What should be the blade velocity of the turbine at inlet in m/s?
a) 40
b) 60
c) 80
d) 25
Answer: a
Explanation: The hydraulic efficiency of a Francis turbine is given by ηh = Vw1.u1/ gH. Substituting the values of the given parameters in the equation, we get blade velocity at the inlet as 40 m/s.
7. The input water power of the Francis turbine is 1.25 times the runner power. What would be the hydraulic efficiency of the turbine ?
a) 60
b) 70
c) 80
d) 90
Answer: c
Explanation: The definition of Hydraulic efficiency in a Francis turbine states that it is the ratio between the Runner power to the shaft power. If input water power is 1.25 times the runner power, the runner power is 1/1.25 = 0.8 Times the water power. Hence, hydraulic efficiency = 80%.
8. The volume flow rate into a Francis turbine is Q m3/s. 0.25Q m3/s volume of water do not flow over the runner blades. What is the mechanical efficiency of the turbine ?
a) 65
b) 75
c) 80
d) Mechanical efficiency cannot be found out from the given information
Answer: d
Explanation: With the given information, we can find the volumetric efficiency and not the mechanical efficiency. If you got this question wrong, its advised to read the question carefully before answering.
9. The volumetric efficiency of a Francis turbine is given to be 90%. If the volume flow rate through the turbine is 25 m 3 /s. What is the flow rate of water over the runner blades (in m 3 /s)?
a) 20
b) 25
c) 22.5
d) 21.5
Answer: c
Explanation: The definition of volumetric efficiency in a Francis turbine states that it is the ratio between the total volume of water flowing over the runner blades to the volume of water entering the turbine. Hence, if Q = 25 m3/s, the volume of water over runner blades = 0.9*25 = 22.5 m 3 /s.
10. The volumetric efficiency of a given turbine is 80%. If volume flow rate of water in given to be 30 m 3 /s, find the volume of water (m 3 ) NOT flowing over the runner blades per second?
a) 5
b) 6
c) 10
d) 12
Answer: b
Explanation: The volume of water flowing over runner blades = 0.8*30 = 24 m 3 /s. The volume of water NOT flowing over the runner blades would then be 30 – 24 = 6 m 3 /s.
11. The power available at the shaft of a Francis turbine is 1 MW. The volume flow rate of water in 25 m 3 /s, whirl velocity at inlet is 10 m/s and blade velocity is 5 m/s. Find the mechanical efficiency ?
a) 65
b) 75
c) 80
d) 90
Answer: c
Explanation: Mechanical efficiency is given by ηm = shaft power / ρQVw1u1. Substituting the given values into this equation, we get mechanical efficiency = 80%.
12. The whirl velocity at inlet is 15 m/s and blade velocity is 10 m/s. The volume flow rate of water in 20 m 3 /s. Find the power output available at the shaft if the mechanical efficiency is 95% ?
a) 2.85
b) 3.075
c) 6.55
d) 0.285
Answer: a
Explanation: Mechanical efficiency is given by ηm = shaft power / ρQV w1u1 . Substituting the given values into this equation, we get shaft power = 2.85 MW.
13. The power output of the shaft is 5 MW. The volume flow rate of water in 10 m 3 /s at an available head of 60 m. Find the overall efficiency of the turbine in % (g = 10 m/s 2 )?
a) 80
b) 82.5
c) 83.3
d) 85
Answer: c
Explanation: The overall efficiency of a Francis turbine is given by ηo = shaft power/ ρQgH. Substituting the given values in this equation, we get overall efficiency = 83.33 %.
14. The volume flow rate of water in 10 m 3 /s at an available head of 60 m (g = 10 m/s 3 ). Find the shaft power if the overall efficiency of the turbine is 90%.
a) 54
b) 5.4
c) 540
d) 0.54
Answer: b
Explanation: The overall efficiency of a Francis turbine is given by ηo = shaft power/ ρQgH. Substituting the given values in this equation, we get shaft power = 5.4 MW.
15. The hydraulic efficiency of a Francis turbine is 90%, the mechanical efficiency is 95% and the volumetric efficiency is assumed to be 100%. Fine the overall efficiency ?
a) 80
b) 85.5
c) 87.5
d) 83.3
Answer: b
Explanation: Overall efficiency is also given by ηo = ηh*ηm*ηv. So, ηo = 0.90*0.95*1 = 0.855 = 85.5%.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Kaplan Turbine Velocity Diagrams”.
1. In a Kaplan turbine, what is the direction of water flow?
a) Axial and then axial
b) Radial and then axial
c) Tangential and then axial
d) Tangential and then radial
Answer: a
Explanation: The Kaplan turbine is an axial flow reaction turbine. The water inlet is axial and the water outlet is axial too.
2. For which of the following values of available heads may Kaplan turbine be used?
a) 250 m
b) 100 m
c) 80 m
d) 50 m
Answer: d
Explanation: The Kaplan turbine is said to be a Low head turbine. The low head ranges from 0 to 60 m. Only 50 m falls in this range and hence, it’s the correct option.
3. In this type of low head turbine, the guide vanes are fixed to the hub of the turbine and are not adjustable. What is this type of turbine called?
a) Francis turbine
b) Kaplan Turbine
c) Propeller Turbine
d) Pelton turbine
Answer: a
Explanation: In a Kaplan turbine, the guide vanes are adjustable and not fixed to the hub of the turbine. Francis and Pelton turbines are not low head turbines. In a propeller turbine, the guide vanes are fixed to the hub of the turbine.
4. The velocity of flow through a Kaplan turbine is 10 m/s. The outer diameter of the runner is 4 m and the hub diameter is 2 m. Find the volume flow rate of the turbine in m3/s?
a) 95
b) 75
c) 85
d) 105
Answer: a
Explanation: The volume flow rate is given by
hydraulic-machines-questions-answers-velocity-diagram-q4
Substituting the given values in the above equation, we get Q = 95 m 3 /s.
5. The velocity of the flow at the inlet of Kaplan turbine is V. In an experimental setup, what could be the possible value of the velocity of the flow at the outlet of Kaplan turbine?
a) V
b) 0.8V
c) 1.2V
d) 2V
Answer: b
Explanation: The flow velocity of turbine at the outlet of the Kaplan turbine will be lesser than that of the inlet due to effects of friction in the blade. Hence, practically a lower value would be obtained. 0.8V is the only option lower than V.
6. Which of the following turbines will have the lowest number of blades in it?
a) Pelton turbine
b) Steam turbine
c) Francis turbine
d) Kaplan turbine
Answer: d
Explanation: As the head for Kaplan turbine is low, the discharge of water through the turbine is high and hence, blade resistance should be low. That’s why Kaplan turbine will have the lowest number of blades.
7. The velocity of the flow through the Kaplan turbine is 25 m/s. The available head of the turbine is 60 m. Find the flow ratio of the turbine (take g = 10 m/s 2 ).
a) 0.65
b) 0.72
c) 0.69
d) 0.75
Answer: b
Explanation: Flow ratio is given by ψ = V f1 / sqrt. The given of head and flow velocity must be substituted in this equation to obtain the flow ratio which comes out to be 0.72.
8. A Kaplan turbine requires a speed ratio of 2. The available head of the turbine is 5 m. What should be the blade velocity of the turbine such that a speed ratio of 2 is maintained (take g = 10 m/s 2 )?
a) 75.75 m/s
b) 63.25 m/s
c) 23.35 m/s
d) 50.00 m/s
Answer: b
Explanation: The speed ratio φ = U/ sqrt. Substitute the value for speed ratio and available head in this equation and rearrange to find U = 63.25 m/s.
9. The flow ratio of a Kaplan turbine is given as 0.7. The available head is 30 m. The outer diameter of the runner is 3.5 m and the hub diameter is 2 m. Find the volume of water flowing through the turbine per second (m 3 /s)?
a) 90
b) 111
c) 125
d) 168
Answer: b
Explanation: We know that
hydraulic-machines-questions-answers-velocity-diagram-q4
We can write V as ψ*). Now, substitute the values in the modified equation to find Q which comes out to be around 111 m 3 /s.
10. In which of the following type of runners in a Kaplan turbine the velocity of whirl at inlet is smaller than the blade velocity?
a) Such a case is practically impossible
b) Slow Runner
c) Medium Runner
d) Fast Runner
Answer: d
Explanation: Considering the velocity diagram of a Kaplan turbine at the inlet for a fast runner, we notice that the whirl velocity is lower the blade velocity along the same direction. They are equal in case of a medium runner.
11. In the outlet velocity triangle of a Kaplan turbine, β 2 = 30 o . V f2 = 5 m/s. What is the relative velocity of the flow at outlet?
a) 10 m/s
b) 5.77 m/s
c) 8.66 m/s
d) 2.88 m/s
Answer: a
Explanation: In the outlet velocity triangle, sin (β 2 ) = V f2 / V r2 . Therefore, V r2 = 5/sin = 10 m/s.
12. In the inlet velocity triangle of a Kaplan turbine, α1 = 45 o . The velocity of flow at inlet = 10 m/s. Find the whirl velocity of water at the inlet of Kaplan turbine?
a) 5 m/s
b) 10 m/s
c) 12.5 m/s
d) 15 m/s
Answer: b
Explanation: In the inlet velocity triangle, tan = V f1 / V w1o, V f1 = V w1 = 10 m/s.
13. The whirl velocity of water at the inlet of the Kaplan turbine is 15 m/s. The velocity of water at inlet of the turbine is 20 m/s. Find the guide vane angle at inlet .
a) 53.13
b) 36.86
c) 45
d) 41.41
Answer: d
Explanation: cos = V w1 / V 1o.
14. The relative velocity of water at the inlet of the Kaplan turbine is 7 m/s. β1 = 75 o . The whirl velocity of the water at inlet is 10 m/s. Find the blade velocity of the turbine?
a) 26.124 m/s
b) 40 m/s
c) 36.124 m/s
d) 60 m/s
Answer: c
Explanation: cos (β 1 ) = (u – V w1 )/ V r1 . Substituting the given values in the above equation and rearranging to find the value of u, we get 36.124 m/s.
15.For the figure given below, find the missing terms in the order of , , and .
hydraulic-machines-questions-answers-velocity-diagram-q15
a) V r1 , α 1 , β 1 , V w1
b) V w1 , β 1 , α 1 , V r1
c) V w1 , α1, β 1 , V r1
d) V r1 , β 1 , α 1 , V w1
Answer: c
Explanation: V w1 is along the direction of u. Hence will be replaced by V w1 . The angle between V1 and u is α 1 , Hence α1 replaces . will then be replaced by V r1 and will be replaced by β 1 , since β 1 is the angle between V r1 and u.
This set of Basic Hydraulic Machines Questions and Answers focuses on “Workdone by Kaplan Turbine”.
1. Kaplan turbine works on________
a) Electrical energy
b) Hydro energy
c) Thermal energy
d) Chemical energy
Answer: c
Explanation: Turbine is a vortex related device. It means turbulence. Turbine is a rotary mechanical device. Kaplan turbine is also called as a water turbine. It works when the blades are adjustable.
2. Kaplan turbine is an ______ reaction turbine
a) Inward flow
b) Outward flow
c) Radial
d) Axial
Answer: a
Explanation: Turbine extracts energy and converts it into useful work. Kaplan turbine is an inward flow reaction turbine. It is one of the most efficient turbines to drive electricity.
3. The Kaplan Turbine is an evolution of ________
a) Francis turbine
b) Pelton wheel
c) Parsons turbine
d) Curtis turbine
Answer: a
Explanation: The Kaplan Turbine is an evolution of Francis turbine. It was invented for an essential purpose. It allowed efficient power production in low head applications. Thus, making it better than Francis.
4. What is the dimension of thermal efficiency of a Kaplan turbine?
a) kg
b) m
c) kg/m
d) Dimensionless
Answer: d
Explanation: Thermal efficiency in thermodynamics is a dimensionless performance. It is a device that is used to measure thermal energy. It is mainly used in internal combustion engines.
5. A Kaplan turbine is used in ________
a) Turbomachinery
b) Pressure drag
c) Aerodynamics
d) Automobiles
Answer: a
Explanation: A Kaplan turbine is a turbomachinery. Turbine extracts energy from fluid flow and converts it into useful work. Turbine is a vortex related device. It means turbulence. Turbine is a rotary mechanical device.
6. The head of the Kaplan ranges from ______
a) 100 to 200 m
b) 250 to 300 m
c) 10 to 70 m
d) 0 m
Answer: c
Explanation: The head of the Kaplan ranges from 10 meters to 70 meters. A Kaplan turbine is a turbomachinery. Turbine extracts energy from fluid flow and converts it into useful work. Turbine is a vortex related device.
7. Nozzles in the Kaplan turbine move due to impact of ________
a) Water
b) Steam
c) Blade
d) Another nozzle
Answer: b
Explanation: Nozzle is moved due to the impact of steam. When the steam hits the nozzle, the pressure is decreased and the temperature is increased.
8. The power output of Kaplan turbine ranges from__________
a) 5 to 200 MW
b) 1000 to 2000 MW
c) 2000 to 3000 MW
d) 5000 and above
Answer: a
Explanation: The power output of Kaplan turbine ranges from 5 mega Watt to 200 mega Watt. It has got runner diameters which ranges from 2 meters to 11 meters. It varies from place to place.
9. Kaplan turbines rotates at a ________ rate
a) Increasing
b) Decreasing
c) Constant
d) Increasing and then decreasing
Answer: c
Explanation: Kaplan turbines rotates at a constant rate. A Kaplan turbine is a turbomachinery. Turbine extracts energy from fluid flow and converts it into useful work. Turbine is a vortex related device.
10. What type of turbine is Kaplan?
a) Impulse
b) Reaction
c) Energy
d) Hydro
Answer: b
Explanation: Kaplan turbine is a reaction turbine. It extracts energy from fluid flow and converts it into useful work. Kaplan turbine is a vortex related device.
11. Kaplan turbine is needed to improve ________
a) Increase Pressure
b) Decrease temperature
c) Change volume
d) Increase efficiency
Answer: d
Explanation: Kaplan turbine is needed to improve efficiencies at low speeds. When we arrange turbine blades in multiple stages. It plays an essential role in turbines.
12. Kaplan turbine is an ________ type turbine
a) Pressure
b) Inward flow
c) Outward flow
d) Velocity
Answer: b
Explanation: Kaplan turbine is an inward flow reaction turbine. It means that the working fluid changes its pressure as it moves through the turbine and gives up its energy.
13. The turbine does not have to be at the lowest point of water flow as long as the water in the draft tube is full.
a) True
b) False
Answer: a
Explanation: The turbine does not have to be at the lowest point of water flow as long as the water in the draft tube is full. A higher turbine located increases the suction and is imparted on the turbine blades by the draft tube.
14. The outlet of the Kaplan turbine is through _______
a) Vane Blades
b) Moving pipeline
c) Draft tube
d) Pump
Answer: c
Explanation: The outlet of the Kaplan turbine is through draft tube. It is a specially shaped tube that helps to decelerate the water and recover its kinetic energy. It happens at a faster rate.
15. Kaplan turbine is most commonly used in propeller turbines.
a) True
b) False
Answer: a
Explanation: Kaplan turbine is most commonly used in propeller turbines. Since, the Kaplan turbines have non-adjustable propeller vanes it is most commonly used. They are used in a wide rage if flow and for other commercial products.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Efficiency of Kaplan Turbine”.
1. For a Kaplan turbine, the whirl velocity at inlet of the turbine is given to be 18 m/s. The blade velocity is given as 25 m/s. What is the hydraulic efficiency for a head of 50 m. Take g = 10 m/s 2 ?
a) 80%
b) 90%
c) 70%
d) 98%
Answer: b
Explanation: The hydraulic efficiency of a Kaplan turbine is given by ηh = V w1.u1 / gH. Substituting the values of the given parameters in the equation, we get hydraulic efficiency = 90%.
2. Which of the following efficiencies for Kaplan Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: a
Explanation: The definition of Hydraulic efficiency in a Kaplan turbine states that it is the ratio between the Runner power to the shaft power. Hence, the correct option is Hydraulic efficiency.
3. The desired hydraulic efficiency of a Kaplan turbine is 98% at a whirl velocity of 20 m/s and a head of 60 m. What should be the blade velocity of the turbine at inlet in m/s? Take g = 10 m/s 2 .
a) 40
b) 60
c) 80
d) 30
Answer: d
Explanation: The hydraulic efficiency of a Kaplan turbine is given by ηh = V w1.u1 / gH. Substituting the values of the given parameters in the equation, we get blade velocity at the inlet as 29.4 m/s which can be roughly approximated to 30 m/s.
4. It is given that the input water power of the Kaplan turbine is 1.10 times the runner power. What would be the hydraulic efficiency of the turbine ?
a) 60.61
b) 70.71
c) 80.81
d) 90.91
Answer: d
Explanation: The definition of Hydraulic efficiency in a Kaplan turbine states that it is the ratio between the Runner power to the shaft power. If input water power is 1.10 times the runner power, the runner power is 1/1.10 = 0.90909 Times the water power. Hence, hydraulic efficiency = 90.91%.
5. Which of the following efficiencies for Kaplan Turbine is described as the ratio between total quantity of water over runner blades to total quantity of water supplied to turbine?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: b
Explanation: The definition of volumetric efficiency in a Kaplan turbine states that it is the ratio between the total volume of water flowing over the runner blades to the volume of water entering the turbine. Hence, the correct option is volumetric efficiency.
6. The volume flow rate into a Kaplan turbine is Q m 3 /s. 0.10Q m 3 /s volume of water do not flow over the runner blades. What further information is required to find the volumetric efficiency of the Kaplan turbine?
a) The numerical value of Q
b) The available head of the turbine
c) The RPM or the blade velocity of the turbine
d) No further information is required
Answer: d
Explanation: The volumetric efficiency of the Kaplan turbine is given by Q – ΔQ/ Q. In this problem, ΔQ = 0.1Q. Thus, Q – ΔQ = 0.9Q. Hence, we get volumetric efficiency as 90%. The problem can be solved with the available information.
7. A student reports the volumetric efficiency of a Kaplan turbine to be 95%. If he measures the volume flow rate through the turbine is 40 m 3 /s. What is the flow rate of water over the runner blades (in m 3 /s)?
a) 38
b) 40
c) 42.11
d) 45
Answer: a
Explanation: The definition of volumetric efficiency in a Kaplan turbine states that it is the ratio between the total volume of water flowing over the runner blades to the volume of water entering the turbine. Hence, if Q = 40 m 3 /s, the volume of water over runner blades = 0.95*40 = 38 m 3 /s.
8. In a Kaplan turbine experiment, the volumetric efficiency of a given turbine is 91%. If volume flow rate of water in given to be 35 m 3 /s, find the volume of water (m 3 ) NOT flowing over the runner blades per second?
a) 4.05
b) 3.15
c) 3.30
d) 2.55
Answer: b
Explanation: The volume of water flowing over runner blades = 0.91*35 = 31.85 m 3 /s. The volume of water NOT flowing over the runner blades would then be 35 – 31.85 = 3.15 m 3 /s.
9. Which of the following efficiencies for Kaplan Turbine is defined as the ratio between the power available at the shaft of the turbine to the power produced by the runner?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: c
Explanation: The definition of Mechanical efficiency in a Kaplan turbine states that it is the ratio between the Shaft power to the Runner power. Hence, the correct option is Mechanical efficiency.
10. The power available at the shaft of a Kaplan turbine is 0.75 MW. The volume flow rate of water in 15 m 3 /s, whirl velocity at inlet is 12 m/s and blade velocity is 5 m/s. Find the mechanical efficiency ?
a) 66.66
b) 75.00
c) 83.33
d) 91.33
Answer: c
Explanation: Mechanical efficiency of a Kaplan Turbine is given by η m = shaft power / ρQVw1u1. Substituting the given values into this equation, we get mechanical efficiency = 83.33%.
11. The whirl velocity at inlet of a Kaplan turbine is 7.5 m/s and blade velocity is 5 m/s. The volume flow rate of water in 20 m3/s. Find the power output available at the shaft if the mechanical efficiency is 93% ?
a) 0.831
b) 0.697
c) 1.362
d) 0.298
Answer: b
Explanation: Mechanical efficiency of a Kaplan Turbine is given by ηm = shaft power / ρQVw1u1. Substituting the given values into this equation, we get shaft power = 697500 W = 0.697 MW.
12. In a Kaplan Turbine experimental setup, the power output of the shaft is 4.325 MW. The volume flow rate of water in 15 m 3 /s at an available head of 50 m. Find the overall efficiency of the turbine in % (g = 10 m/s 2 )?
a) 57.66
b) 83.63
c) 81.33
d) 79.95
Answer: a
Explanation: The overall efficiency of a Kaplan turbine is given by ηo = shaft power/ ρQgH. Substituting the given values in this equation, we get overall efficiency = 57.66 %.
13. The hydraulic efficiency of a Kaplan turbine is 95%, the mechanical efficiency is 93% and the volumetric efficiency is assumed to be 100%. Fine the overall efficiency ?
a) 80.05
b) 93.15
c) 87.55
d) 88.35
Answer: d
Explanation: For a Kaplan Turbine, the overall efficiency is also given by ηo = ηh*ηm*ηv. So, ηo = 0.95*0.93*1 = 0.8835 = 88.35%.
14. Which of the following efficiencies for Kaplan Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet?
a) Hydraulic efficiency
b) Volumetric efficiency
c) Mechanical efficiency
d) Overall efficiency
Answer: d
Explanation: The definition of Overall efficiency in a Kaplan turbine states that it is the ratio between the Shaft power to the Water power. Hence, the correct option is Overall efficiency.
15. In Kaplan turbine apparatus, the volume flow rate of water in 15 m 3 /s at an available head of 55 m (g = 10 m/s 2 ). Find the shaft power if the overall efficiency of the turbine is 95%.
a) 78.3
b) 7.83
c) 783
d) 0.783
Answer: b
Explanation: The overall efficiency of a Kaplan turbine is given by ηo = shaft power/ ρQgH. Substituting the given values in this equation, we get shaft power = 7.83 x 106 W = 7.83 MW.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Types of Draft Tube”.
1. Draft tube is also called_______
a) Straight divergent tube
b) Simple elbow tube
c) Thermal tube
d) Elbow tube with varying cross section
Answer: a
Explanation: Draft tube is one of the most commonly used in the Kaplan turbine. It works as an outlet at the Kaplan turbine. Draft tube is also called straight divergent tube.
2. A draft tube helps in converting kinetic energy into________
a) Electrical work
b) Mechanical work
c) Chemical work
d) Thermal work
Answer: b
Explanation: Turbine extracts energy and converts it into useful work. Turbine is a vortex related device. It means turbulence. Steam turbine converts energy into mechanical work by extracting thermal energy from pressurized steam.
3. Most common application of the draft tube is ______
a) Rotor
b) Motor
c) Pump
d) Filter
Answer: c
Explanation: Most common application of the draft tube is different types of pumps. It plays an important role in the putlet of the pump and the turbine.
4. Draft tube consists of conical diffuser with angles of______
a) 10 deg
b) 20 deg
c) 30 deg
d) 40 deg
Answer: a
Explanation: Draft tube consists of conical diffuser with angles of 10 degrees with respect to its position, Draft tubes are situated in the outlet of the turbine.
5. What is the purpose of a Draft tube?
a) To prevent flow separation
b) To avoid Pressure drag
c) To prevent rejection of heat
d) To increase efficiency
Answer: a
Explanation: Draft tube in a turbine and pumps helps to prevent flow separation in order to increase the turbine efficiency and increase its performance.
6. What is the maximum value of efficiency in a draft tube?
a) 100
b) 50
c) 90
d) 40
Answer: c
Explanation: The maximum value of efficiency in a draft tube is 90 percent. It cannot exceed more than 90 percent because of the heat losses due to flow of fluid.
7. The simple elbow draft tube is placed close to the_______
a) Head race
b) Tail race
c) Tank
d) Nozzle
Answer: b
Explanation: The simple elbow draft tube is placed close to the tail race. It consists of an extended elbow type tube. It is mainly used in the Kaplan turbine. It is placed close to the tail race of the turbine.
8. Turbine that consists of draft tubes is called as__________
a) Impulse turbine
b) Curtis turbine
c) Rateau turbine
d) Reaction turbine
Answer: d
Explanation: A turbine that consists of draft tubes is called as a reaction turbine. Reaction turbines make maximum use of the draft tubes for improving its performance characteristics.
9. Which of the following is a 50 percent reaction turbine?
a) Parsons turbine
b) Curtis turbine
c) Rateau turbine
d) Pelton wheel
Answer: a
Explanation: A turbine that consists of moving nozzles which are alternating with the fixed nozzles is called as a reaction turbine. When the steam hits the nozzle, the pressure is decreased and the temperature is increased. It is also called as Parson’s turbine.
10. The simple elbow draft tube helps to cut down the cost of excavation.
a) True
b) False
Answer: a
Explanation: The simple elbow draft tube helps to cut down the cost of excavation. The simple elbow draft tube is placed close to the tail race. It consists of an extended elbow type tube. It is mainly used in the Kaplan turbine. It is placed close to the tail race of the turbine.
11. The exit diameter for a simple elbow draft tube should be________
a) Large
b) Small
c) Very small
d) Same
Answer: a
Explanation: The exit diameter for a simple elbow draft tube should be large as possible. It helps to cut down the cutdown the cost and recover the kinetic energy at the outlet of runner. The simple elbow draft tube is placed close to the tail race.
12. Properties that do not affect a draft tube is _______
a) Pressure
b) Temperature
c) Pressure velocity
d) Velocity
Answer: b
Explanation: Temperature does not affect the performance of the draft tube. With increase and decrease of temperature of fluid in a draft tube, the draft tube remains the same.
13. The other name for elbow with varying cross section tube is called_____
a) Pressure tube
b) Bent draft tube
c) Velocity tube
d) Sink tube
Answer: b
Explanation: The other name for elbow with varying cross section tube is called bent draft tube. It is so called because only the bent part is of varying cross section. Thus, the answer is bent draft tube.
14. What is the efficiency of the simple elbow type draft tube?
a) 10
b) 30
c) 60
d) 90
Answer: c
Explanation: The efficiency of the simple elbow type draft tube is 60 percent. The exit diameter for a simple elbow draft tube should be large as possible. It helps to cut down the cutdown the cost and recover the kinetic energy at the outlet of runner. The simple elbow draft tube is placed close to the tail race.
15. The horizontal portion of the draft tube is usually bent to prevent entry of air from the exit end.
a) True
b) False
Answer: a
Explanation: The horizontal portion of the draft tube is usually bent to prevent entry of air from the exit end. This might lead to a mixing up of gases. In order to avoid this, it is important to avoid air entry from exit.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Theory on Draft Tube”.
1. The efficiency of the draft tube is ratio of ________
a) Pressure energy by kinetic energy
b) Kinetic energy by Pressure energy
c) Kinetic energy into mechanical energy
d) Pressure into mechanical
Answer: b
Explanation: The efficiency of the draft tube is defined as the ratio of actual conversion of kinetic energy into the pressure energy. The pressure energy and kinetic energy is present at the inlet of the draft tube.
2. Draft tubes are not used in which of the following turbines?
a) Francis
b) Reaction
c) Kaplan
d) Pelton
Answer: d
Explanation: Turbine extracts energy and converts it into useful work. Turbine is a vortex related device. Draft tubes are not used in Pelton wheels. Draft tube is a tube that is installed in power turbines.
3. The draft tube at the exit of the nozzle increases the _______
a) Temperature
b) Pressure
c) Volume of the flow
d) Density of flow
Answer: b
Explanation: The draft tube at the exit of the nozzle increases the pressure in the fluid. It increases it at the expense of its velocity. This means that the turbine can reduce its pressure without fear of back flow to the tail race.
4. Efficiency of a draft tube gives __________
a) Temperature difference
b) Pressure difference
c) Kinetic energy difference
d) Density of flow
Answer: c
Explanation: The efficiency of the draft tube gives difference of the kinetic energy between the inlet and the outlet tube losses. The efficiency of the draft tube is defined as the ratio of actual conversion of kinetic energy into the pressure energy.
5. Cavitation in a draft tube occurs when _______
a) Temperature difference
b) Pressure drop
c) Kinetic energy difference
d) Density of flow
Answer: b
Explanation: Cavitation in a draft tube occurs when pressure drop takes place. The absolute pressure falls below the saturated vapour pressure of the water for the given temperature.
6. Which among the following is an important parameter to avoid cavitation?
a) Tail race length
b) Head race length
c) Height of draft tube
d) Pump
Answer: c
Explanation: Cavitation in a draft tube occurs when pressure drop takes place. The absolute pressure falls below the saturated vapour pressure of the water for the given temperature. Height of the draft tube is an important parameter to avoid cavitation.
7. The draft tube is situated in the _______
a) Inlet
b) Outlet
c) Tank
d) Nozzle
Answer: b
Explanation: The simple elbow draft tube is placed close to the inlet of the turbine. It consists of an extended elbow type tube. It is mainly used in the Kaplan turbine. It is placed close to the tail race of the turbine.
8. Which equation is applied to determine the flow?
a) Newtons equation
b) Rutherford’s equation
c) Bernoulli’s equation
d) Faradays equation
Answer: c
Explanation: Bernoulli’s equation is used to determine the flow of the fluid from inlet to the outlet. It also helps in avoiding cavitation. Cavitation in a draft tube occurs when pressure drop takes place.
9. Height of the draft tube is denoted by _____
a) H
b) h
c) z
d) x
Answer: c
Explanation: Height of the draft tube is denoted by ‘z’. It is equated to z2, which is attached at the outlet of the turbine. Thus, the universal symbol to denote height of the draft tube is ‘z’.
10. Draft tube allows turbine to be placed above the tail race.
a) True
b) False
Answer: a
Explanation: The draft tube helps to cut down the cost of excavation. The draft tube is placed close to the tail race. The turbine pressure head is increased by decreasing the velocity at the draft tube. Draft tube allows turbine to be placed above the tail race.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Efficiency of Draft Tube”.
1. The efficiency of the draft tube depends on the ______
a) Heat
b) Pressure
c) Temperature
d) Pressure and temperature
Answer: d
Explanation: The efficiency of the draft tube is defined as the ratio of actual conversion of kinetic energy into the pressure energy. The pressure energy and kinetic energy is present at the inlet of the draft tube.
2. Draft tubes have _________ shafts
a) Horizontal
b) Vertical
c) Circular
d) Cross sectional
Answer: b
Explanation: Draft tubes have vertical shafts. The pressure energy and kinetic energy is present at the inlet of the draft tube.
3. Draft tubes are situated at the outlet in____________
a) Pelton
b) Reaction
c) Kaplan
d) Francis
Answer: a
Explanation: Turbine extracts energy and converts it into useful work. Turbine is a vortex related device. Draft tubes are not used in Pelton wheels. Draft tube is a tube that is installed in power turbines.
4. Efficiency of a draft tube is directly proportional to its __________
a) Temperature
b) Pressure
c) Velocity
d) Density
Answer: c
Explanation: The efficiency of the draft tube gives difference of the kinetic energy between the inlet and the outlet tube losses. It is directly proportional to its velocity.
5. Z is a draft tube is _______
a) Temperature difference
b) Pressure drop
c) Kinetic energy difference
d) Datum head
Answer: d
Explanation: Height of tail race which is referenced as datum line is equal to zero. It is denoted as ‘Z’. It plays an important role to determine its efficiency.
6. Draft tube operates at ______
a) Same efficiency
b) Different efficiency
c) Turbine
d) Pump
Answer: a
Explanation: Draft Tube allows turbine to be placed above the tail race and simultaneously allows it to operate at the same efficiency if it was placed at the tail race.
7. The draft tube is an ________
a) Interior tube
b) Exterior tube
c) Tank depth alternator
d) Nozzle tube
Answer: b
Explanation: The simple elbow draft tube is placed close to the tail race. It consists of an extended elbow type tube. It is mainly used in the Kaplan turbine. It is placed close to the tail race of the turbine.
8. What type of pressure does the draft tube depend upon?
a) Gauge pressure
b) Atm pressure
c) Normal pressure
d) Normal and Atm pressure
Answer: a
Explanation: Draft tube is mainly used to determine the gauge pressure of the turbine and pumps and is located at the inlet of the turbine.
9. Gauge pressure of the draft tube is denoted by _____
a) P
b) h
c) z
d) x
Answer: a
Explanation: Gauge pressure of the draft tube is denoted by ‘P’. It helps to determine the pressure of the fluid in the draft tube.
10. Draft tube allows turbine to be placed below the tail race.
a) True
b) False
Answer: b
Explanation: The draft tube helps to cut down the cost of excavation. The draft tube is placed close to the tail race. The turbine pressure head is increased by decreasing the velocity at the draft tube. Draft tube allows turbine to be placed above the tail race.
This set of Hydraulic Machines Quiz focuses on “Derivation of Specific Speed”.
1. Specific speed is denoted by ________
a) N
b) n
c) N s
d) S
Answer: c
Explanation: Specific speed is denoted by N s . It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
2. Specific speeds are used in pumps to determine ________
a) Temperature
b) Reaction speed
c) Suction specific speed
d) Wheel speed
Answer: c
Explanation: Specific speeds are used in pumps to determine. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
3. The tube at the exit of the nozzle increases the _______
a) Temperature
b) Pressure
c) Volume of the flow
d) Density of flow
Answer: b
Explanation: The draft tube at the exit of the nozzle increases the pressure in the fluid. It increases it at the expense of its velocity. This means that the turbine can reduce its pressure without fear of back flow to the tail race.
4. Specific speed is used to characterize _______
a) Turbomachinery speed
b) Flow speed
c) Energy flow
d) Heat generated
Answer: a
Explanation: Specific speed is used to characterize Turbomachinery speed. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
5. Specific speed predicts the shape of a/an _________
a) Pump
b) Density head
c) Impeller
d) Motor
Answer: c
Explanation: Specific speed predicts the shape of an impeller. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
6. What helps in categorizing the impellers?
a) Quasi static number
b) Rotor
c) Height of draft tube
d) Pump
Answer: a
Explanation: The impellers are categorized using a quasi static non dimensional number. It helps in determining the impellers time and proportional quantities.
7. Imperial units is defined as _________
a) Temperature by pressure
b) Tail race and head race
c) Revolutions per minute
d) Turbine performance
Answer: c
Explanation: In Imperial units it is defined as the speed in revolutions per minute at which a geometrically similar impeller would operate if it were of such a size as to deliver one gallon per minute against one foot of hydraulic head.
8. Ratio of pump or turbine with reference pump or turbine is called as _________
a) Efficiency
b) Performance
c) Heat generated
d) Relative velocity
Answer: b
Explanation: Ratio of pump or turbine with reference pump or turbine is called as the performance of that particular turbine or pump.
9. Low specific speed in hydraulic head is developed due to _________
a) Mass flow rate
b) Increase in temperature
c) Centrifugal force
d) Increase in pressure
Answer: c
Explanation: Low specific speed with a radial flow in impellers are developed in hydraulic head principally due to centrifugal force. Pumps having higher specific speed develop a head that is partly by axial force.
10. Centrifugal pump impellers have speed ranging from ________
a) 500- 10000
b) 50- 100
c) 200-300
d) 0-50
Answer: a
Explanation: Centrifugal pump impellers have speed ranging from 500- 10000 English units. IT has got radial flow with pumps mixed with axial flow pumps.
11. What is the unit of specific speed in metric system?
a) m.s
b) m/s
c) m 3 /s
d) m
Answer: c
Explanation: The unit of specific speed in the metric system is given as m 3 /s. Specific speed is denoted by N s . It is used to characterize speeds in turbo machinery.
12. Specific speed develop a hydraulic flow through the centrifugal pumps.
a) True
b) False
Answer: a
Explanation: Specific speed develop a hydraulic flow through the centrifugal pumps. Specific speed is denoted by N s . It is used to characterize speeds in turbo machinery. With the increase in specific speeds, diameter of the impellers increases.
13. Net suction speed is used in problems with cavitation.
a) True
b) False
Answer: a
Explanation: Net suction speed is used in problems with cavitation during the pump’s operation on the suction side. It is defined by centrifugal and axial pump.
14. Low specific speed in hydraulic head is developed due to _________
a) Mass flow rate
b) Increase in temperature
c) Centrifugal force
d) Increase in pressure
Answer: c
Explanation: Low specific speed with a radial flow in impellers are developed in hydraulic head principally due to centrifugal force. Pumps having higher specific speed develop a head that is partly by axial force.
15. The runner diameter in a turbine is denoted as __________
a) A
b) D r
c) R r
d) D e
Answer: d
Explanation: The runner diameter in a turbine is denoted as ‘D e ’. Its SI unit is meters. It plays an essential role in improving the efficiency of the turbine. As the efficiency of the turbine is related to its design and structure.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Significance of Specific Speed”.
1. Specific speed is the speed of the turbine which is similar to its ________
a) Temperature difference
b) Pressure difference
c) Aspect ratio
d) Speed of rotor
Answer: c
Explanation: Specific speed is the speed of the turbine which is similar to its aspect ratio. Specific speed is denoted by N s . It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
2. Specific speeds are used in pumps to determine ________
a) Temperature
b) Reaction speed
c) Suction specific speed
d) Wheel speed
Answer: c
Explanation: Specific speeds are used in pumps to determine. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
3. Specific speed develops a unit power under a unit _______
a) Temperature
b) Pressure
c) Volume of the flow
d) Head
Answer: d
Explanation: Specific speed develops a unit power under a unit head of the turbine. The unit head of the turbine plays an important role in denoting the specific speed of the turbine.
4. Impeller in a motor is used to _________
a) Change temperatures
b) Change Pressure
c) Kinetic energy change
d) Change density
Answer: b
Explanation: Impellers that are present in motors are used to increase or decrease the pressure of the fluid flow in the turbines. Thus, the correct option is ‘b’.
5. Hydraulic head is also called as _________
a) Pressure head
b) Density head
c) Kinetic head
d) Piezometric head
Answer: d
Explanation: Hydraulic head is also called a Piezometric head. It is a measurement of the liquid pressure above the geodetic datum. Hydraulic head is usually measured as a liquid in surface elevation.
6. Specific speed of a Pelton wheel with single jet is _______
a) 8.5 to 30
b) 30 to 51
c) 51 to 225
d) 230 to 500
Answer: a
Explanation: Specific speed of a Pelton wheel with a single jet is equal to 8.5 to 30. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
7. Specific speed is an index used to predict _______
a) Head race distance
b) Tail race distance
c) Tank dimensions
d) Turbine performance
Answer: d
Explanation: Specific speed of a turbine is used to predict its turbine performance. Specific speeds are used in pumps to determine. Specific speed is denoted by N s . It is used to characterize speeds in turbo machinery.
8. Specific speed of a Pelton wheel with multiple jets is _______
a) 8.5 to 30
b) 30 to 51
c) 51 to 225
d) 230 to 500
Answer: b
Explanation: Specific speed of a Pelton wheel with multiple jets is equal to 30 to 51. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
9. Specific speed of a Francis turbine is _______
a) 8.5 to 30
b) 30 to 51
c) 51 to 225
d) 230 to 500
Answer: c
Explanation: Specific speed of a Francis turbine is equal to 51 to 225. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
10. Specific speed of a Kaplan turbine is _______
a) 8.5 to 30
b) 30 to 51
c) 51 to 225
d) 355 to 860
Answer: d
Explanation: Specific speed of a Kaplan turbine is equal to 51 to 225. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. Some of the main examples of turbomachinery are turbines. Specific speed plays an important role in the turbine.
11. Specific speed less than 500 are called _________
a) Positive displacement pumps
b) Negative displacement pumps
c) Draft tubes
d) Tanks
Answer: a
Explanation: Specific speed less than 500 are called positive displacement pumps. Centrifugal pump impellers have speed ranging from 500- 10000 English units. IT has got radial flow with pumps mixed with axial flow pumps.
12. With the increase in specific speeds, ________
a) Head race distance increases
b) Tail race distance increases
c) Tank dimensions increases
d) Diameters of impeller increases
Answer: d
Explanation: Specific speed of a turbine is used to predict its turbine performance. Specific speeds are used in pumps to determine. Specific speed is denoted by Ns. It is used to characterize speeds in turbo machinery. With the increase in specific speeds, diameter of the impellers increases.
13. Specific speed is used to predict desired pump or turbine performance.
a) True
b) False
Answer: a
Explanation: Specific speed is used to predict desired pump or turbine performance. It predicts the general shape of the impeller. Thus, it is a true statement.
14. Once we know the desired functions of the specific speed, it is easier to calculate its components units.
a) True
b) False
Answer: a
Explanation: Yes, Once we know the desired functions of the specific speed, it is easier to calculate its components units. Specific speed is used to predict desired pump or turbine performance. It predicts the general shape of the impeller.
This set of Hydraulic Machines Problems focuses on “Unit Quantities Usage”.
1. Which among the following is not a unit quantity of turbine?
a) Unit speed
b) Unit discharge
c) Unit power
d) Unit temperature
Answer: d
Explanation: Unit discharge, unit speed and unit power the three basic functions of the turbine. It plays an important role in determining the specific speeds and to increase the overall output efficiency of the turbine.
2. What does DMU stand for?
a) Density matter usage
b) Direct material usage
c) Density material usage
d) Depth matter usage
Answer: b
Explanation: DMU in hydraulic machines and turbo machinery stands for Direct material usage. It plays an important role in specifying the unit quantities.
3. Unit speed is the speed of the turbine operating under________
a) One-meter head
b) Pressure head
c) Volumetric head
d) Draft tube
Answer: a
Explanation: Specific speed develops a unit power under a unit head of the turbine. The unit head of the turbine plays an important role in denoting the specific speed of the turbine. Unit speed is the speed of the turbine operating under one-meter head.
4. One dyne is equal to ________ N.
a) 10
b) 100
c) 1000
d) 10-5
Answer: d
Explanation: One dyne is equal to 10-5 N. It is in accordance to the USCS . Thus the correct option is ‘d’.
5. What is symbol for unit speed?
a) S
b) N
c) Ns
d) Nu
Answer: d
Explanation: The most commonly used symbol of unit speed is Nu. Unit speed is the speed of the turbine operating under one-meter head. Thus, the option is ‘c’.
6. Unit speed of a single jet in a turbine is _______
a) 100 m/s
b) 300 m/s
c) 500 m/s
d) 800 m/s
Answer: d
Explanation: Unit speed of a single jet in a turbine is around 800 m/s. The most commonly used symbol of unit speed is N u . Unit speed is the speed of the turbine operating under one-meter head. Thus, the option is ‘c’.
7. Unit speed is directly proportional to________
a) Head race distance
b) Specific speed
c) Pressure
d) Turbine performance
Answer: b
Explanation: Specific speed of a turbine is used to predict its turbine performance. Specific speeds are used in pumps to determine. Unit speed is directly proportional to its specific speed. Specific is takes place at the inlet and the outlet of the turbines.
8. Unit discharge is the discharge through the turbine when the head of the turbine is ________
a) High
b) Zero
c) Unity
d) Low
Answer: c
Explanation: Unit discharge is the discharge through the turbine when the head of the turbine is unity. Unit discharge is one of the major unit quantities that determine the overall efficiency of the turbine.
9. Unit discharge is denoted as _______
a) D u
b) Q u
c) S u
d) N u
Answer: b
Explanation: The basic symbol of unit discharge is given as Q u . Unit discharge is the discharge through the turbine when the head of the turbine is unity. Unit discharge is one of the major unit quantities that determine the overall efficiency of the turbine.
10. Unit discharge is directly proportional to _______
a) Head race distance
b) Discharge of fluid in the turbine.
c) Pressure
d) Turbine performance
Answer: b
Explanation: Unit discharge is directly proportional to the discharge of fluid in the turbine. Unit discharge is the discharge through the turbine when the head of the turbine is unity. Unit discharge is one of the major unit quantities that determine the overall efficiency of the turbine.
11. Unit quantities are physical quantities _________
a) With numerical variables
b) Without numerical variables
c) With different sets
d) With unit difference
Answer: b
Explanation: Unit quantities are physical quantities without numerical variables. Unit is a way to assign measurement to any dimensional quantity.
12. Dyne cm is a Torque measurement unit.
a) True
b) False
Answer: a
Explanation: Dyne cm is a Torque measurement unit. One dyne is equal to 10-5 N. It is in accordance to the USCS .
13. Unit quantities play an important role in determining the dimensional quantities.
a) True
b) False
Answer: a
Explanation: Yes, Unit quantities play an important role in determining the dimensional quantities as they denote the unit quantities usage and also its dimensions.
14. Unit power is developed by the turbine when the head of the turbine is unity.
a) True
b) False
Answer: a
Explanation: Yes, Unit power is developed by the turbine when the head of the turbine is unity. Unit power is one of the major quantities that influence the overall efficiency of the turbine and thus, plays an important role.
This set of Hydraulic Machines Assessment Questions and Answers focuses on “Constant Head Curves”.
1. Constant head curves are also called as _______
a) Head race curves
b) Tail race curves
c) Main characteristic curves
d) Impeller curves
Answer: c
Explanation: Constant head curves are also called as main characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
2. The speed of the turbine in a constant head curve is varied by __________
a) Temperature change
b) Reaction speed change
c) Changing the gate opening
d) Wheel speed change
Answer: c
Explanation: The speed of the turbine in a constant head curve is varied by maintaining a constant head. When we maintain a constant head, the speed of the turbine is varied by regulating the flow of fluid through a sluice gate.
3. Constant speed curves travel at constant speed when the value is equal to _______
a) 0
b) 1
c) 2
d) 3
Answer: b
Explanation: Constant speed curves detect the performance at different conditions. Characteristic curves of a turbine play an important role. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
4. Power of a turbine is measured ______
a) Mechanically
b) Electrically
c) Chemically
d) Thermally
Answer: a
Explanation: Power of a turbine is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
5. Which among the following is not a parameter to determine the efficiency of the turbine?
a) Unit speed
b) Unit power
c) Unit volume
d) Unit discharge
Answer: c
Explanation: Unit volume is not a parameter to determine the efficiency of the turbine. Power of a turbine is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
6. Which among the following is not an important parameter to determine the performance of the turbine?
a) Speed
b) Discharge
c) Head
d) Volume of tank
Answer: d
Explanation: Volume of tank is not an important parameter to determine the efficiency of the turbine. These are not drawn in the curves pertaining its efficiency.
7. Which among the following is not a type of curve?
a) Logarithimic curve
b) Straight curve
c) Pressure vs power
d) Efficiency vs speed
Answer: c
Explanation: Pressure vs power is not a characteristic curve that determines the overall efficiency of the turbine. This relation does not exist.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
Answer: b
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. Overall efficiency vs what is drawn to determine the turbine performance?
a) Unit Discharge
b) Unit speed
c) Unit power
d) Unit pressure
Answer: b
Explanation: One of the graphs to determine the performance of the turbine is overall efficiency vs the unit speed of the turbine. Unit speed is a speed of the fluid flow from inlet to the outlet of the turbine.
10. Constant discharge takes place due to _______
a) Unit Discharge
b) Unit speed
c) Unit power
d) Unit pressure
Answer: b
Explanation: Unit discharge is directly proportional to the discharge of fluid in the turbine. Unit discharge is the discharge through the turbine when the head of the turbine is unity. Unit discharge is one of the major unit quantities that determine the overall efficiency of the turbine.
11. All the characteristic curves are drawn with respect to __________
a) Unit Discharge
b) Unit speed
c) Unit power
d) Unit pressure
Answer: b
Explanation: All the characteristic curves that specify different parameters in a turbine are drawn with respect to its unit speed. Unit discharge, unit power and overall efficiency vs the unit speed is drawn.
12. Constant head curves are also called as _______
a) Head race curves
b) Tail race curves
c) Main characteristic curves
d) Impeller curves
Answer: c
Explanation: Constant head curves are also called as main characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
13. In constant speed curves, the speed is kept a constant varying its head.
a) True
b) False
Answer: a
Explanation: Constant speed curves are also called as operating characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
14. In all the characteristic curves, the overall efficiency is aimed at the maximum value.
a) True
b) False
Answer: a
Explanation: Yes, In all the characteristic curves, the overall efficiency is aimed at the maximum value. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
15. Constant efficiency curves are plotted using _______
a) Constant head curves
b) Constant speed curves
c) Main characteristic curves
d) Constant speed and constant head
Answer: d
Explanation: Constant efficiency curves are plotted using both Constant speed and constant head. Constant efficiency curves are also called as Muschel curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Constant Speed Curves”.
1. Constant speed curves are also called as _______
a) Main characteristic curves
b) Turbine curves
c) Tail race curves
d) Impeller curves
Answer: c
Explanation: Constant speed curves are also called as main characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
2. Constant speed curve is denoted as _____
a) T
b) V
c) c
d) V
Answer: c
Explanation: The constant speed curve is denoted as ‘c’. It is also called as called as the main characteristic curve. It plays an important role in determining the performance of the turbine.
3. Constant speed curves are ________
a) Scalar quantities
b) Vector quantities
c) Constant quantities
d) Different conditions
Answer: b
Explanation: Constant speed curves detect the performance at different conditions. Constant speed curves are vector quantities.
4. Constant speed is measured _________
a) Mechanically
b) Electrically
c) Chemically
d) Thermally
Answer: a
Explanation: Constant speed is measured is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
5. Constant speed curves are determined by the _________
a) Arc length
b) Power
c) Heat
d) Temperature
Answer: c
Explanation: Constant speed curves are determined by the unit arc length. Constant speed is measured is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
6. Which component is necessary for writing the velocity equation?
a) Cos component
b) Sine Component
c) Cos and sine component
d) Independent
Answer: c
Explanation: Both the cosine and sine component are necessary for determining and writing down the equation for the velocity. It also helps to determine the characteristic curves using the equation.
7. Which among the following is not a shape for a curve?
a) Logarithmic curve
b) Helix curve
c) Straight curve
d) Speed curve
Answer: d
Explanation: Speed curve is not a shape of a characteristic curve. Constant speed is measured is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
8. How do we plot points in a curve?
a) Analytical approach
b) General approach
c) Tail approach
d) Head approach
Answer: a
Explanation: The plotting of curves take place in an analytical approach. It is very essential for the plotting of the characteristic points.
9. Plotting sine curve will take place along the _________
a) y axis
b) x axis
c) z axis
d) x and z
Answer: b
Explanation: Plotting sine curve will take place along the x axis. It is the motion of the x-y plane that will occur in space.
10. In analytical approach, dp= __________
a) vdt
b) v
c) dt
d) dx
Answer: a
Explanation: In any sort of analytical approach, the equation for dp = vdt. It takes place when the sine component and cosine components equal to one.
11. The equation is general approach is called as central difference.
a) True
b) False
Answer: a
Explanation: The equation is general approach is called as central difference. All the characteristic curves that specify different parameters in a turbine are drawn with respect to its unit speed.
12. The approximate value of the constant speed curve is given by ratio of ________
a) dy/dp
b) dx/dp
c) dt/dx
d) dt/dy
Answer: a
Explanation: The approximate value of the constant speed curve is given by ratio of dy/dp. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
13. In constant speed curves, the velocity is kept a constant varying its head.
a) True
b) False
Answer: b
Explanation: Constant speed curves are also called as operating characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
14. The performance of a characteristic curve is kept at a high value.
a) True
b) False
Answer: a
Explanation: Yes, In all the characteristic curves, the performance is aimed at the maximum value. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Governing of Turbines – 1”.
1. In nozzle governing, the flow rate of steam is regulated by _________
a) Nozzles
b) Pumping
c) Drafting
d) Intercooling
Answer: a
Explanation: The process of controlling the flow rate of a substance is called as governing. It is done by maintaining the speed of rotation at a constant rate. In nozzle governing, the flow rate of steam is regulated by nozzles.
2. The flow rate of steam is controlled by regulating the _________
a) Steam
b) Pressure
c) Temperature
d) Speed
Answer: b
Explanation: The process of controlling the flow rate is called as governing. It is done to maintain its speed at a constant rate during rotation of the turbine rotor. The flow rate of steam is controlled by regulating the pressure.
3. The main function of nozzle is to __________
a) Varying temperatures
b) Pressure variations
c) Load variations
d) Heat variations
Answer: b
Explanation: The main function of nozzle is to vary the pressure of fluid passing through the nozzle. It is done by opening and shutting the sets of nozzles. Thus, its main function is to regulate pressure of the fluid.
4. What is primary objective of steam turbine governing?
a) Maintain constant speed
b) Maintain constant pressure
c) Maintain constant temperature
d) Maintain constant expansion
Answer: a
Explanation: The primary objective of steam turbine governing is to maintain a constant speed at varying loads. That means, irrespective of the load that is developed in the turbine, the speed remains a constant.
5. What is the purpose of a steam turbine governing?
a) Controls speed
b) Controls flow rate
c) Controls volume
d) Controls discharge
Answer: b
Explanation: The main purpose of the steam turbine governing is to control the flow rate of steam in the turbine. It also helps in regulating the load that is developed.
6. Which among the following control the flow rate?
a) Valve
b) Pump
c) Head
d) Tank pipe
Answer: a
Explanation: Flow rate of the tank is controlled by the valve. The actuation of individual valve closes. This corresponds to the set of nozzle thereby controlling the actual flow rate of the fluid passing through the valve.
7. The advantage of nozzle governing is that no regulating pressure is applied.
a) True
b) False
Answer: a
Explanation: The advantage of nozzle governing is that no regulating pressure is applied. The actuation of individual valve closes the corresponding set of nozzle. Thus, controlling the flow rate.
8. During the steam turbine governing, what remains a constant?
a) Speed of rotation
b) Flow rate
c) Pump head
d) Volume of fluid
Answer: a
Explanation: During the steam turbine governing the speed of rotation remains a constant. The main purpose of the steam turbine governing is to control the flow rate of steam in the turbine. It also helps in regulating the load that is developed.
9. When do we apply by pass governing?
a) When turbine is overloaded
b) When Unit speed decreases
c) When Unit power increases
d) When Unit pressure decreases
Answer: a
Explanation: The main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations. This happens occasionally in the working of the turbine. During this, a bypass valve is used.
10. When bypass valve is opened to _______
a) Increase Pressure
b) Increase Unit speed
c) Increase Unit power
d) Increase the amount of fresh steam
Answer: d
Explanation: When a by pass valve is opened, a fresh steam is introduced into the turbine, thereby increasing the amount of fresh steam. The main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations.
11. What is the unit of steam rate?
a) kg
b) kg/m
c) kg/kWh
d) N/m
Answer: c
Explanation: The unit of stream is equal to kg/kWh. In the process of throttle governing, it is denoted by the symbol ‘a’. The variation of the steam consumption rate with the turbine load during governing is linear.
12. With the increase in load, Energy in the turbine ________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. Combination governing involves usage of two or more governing.
a) True
b) False
Answer: a
Explanation: Yes, Combination governing involves usage of two or more governing. Most usage is the by pass and the nozzle governing as they tend to match the load on the turbine. Thus, increasing its efficiency.
14. When the mechanical speed of the shaft increases beyond 110 percent, we use _________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the mechanical speed of the shaft increases beyond 110 percent, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
This set of Hydraulic Machines Questions and Answers for Experienced people focuses on “Governing of Turbines – 2”.
1. In nozzle governing, the flow rate of steam is regulated by _________
a) Nozzles
b) Pumping
c) Drafting
d) Intercooling
Answer: a
Explanation: The process of controlling the flow rate of a substance is called as governing. It is done by maintaining the speed of rotation at a constant rate. In nozzle governing, the flow rate of steam is regulated by nozzles.
2. The flow rate of steam is controlled by regulating the_________
a) Steam
b) Pressure
c) Temperature
d) Speed
Answer: b
Explanation: The process of controlling the flow rate is called as governing. It is done to maintain its speed at a constant rate during rotation of the turbine rotor. The flow rate of steam is controlled by regulating the pressure.
3. The main function of nozzle is to __________
a) Varying temperatures
b) Pressure variations
c) Load variations
d) Heat variations
Answer: b
Explanation: The main function of nozzle is to vary the pressure of fluid passing through the nozzle. It is done by opening and shutting the sets of nozzles. Thus, its main function is to regulate pressure of the fluid.
4. What is primary objective of steam turbine governing?
a) Maintain constant speed
b) Maintain constant pressure
c) Maintain constant temperature
d) Maintain constant expansion
Answer: a
Explanation: The primary objective of steam turbine governing is to maintain a constant speed at varying loads. That means, irrespective of the load that is developed in the turbine, the speed remains a constant.
5. Which among the following is not a parameter to determine the efficiency of the turbine?
a) Unit speed
b) Unit power
c) Unit volume
d) Unit discharge
Answer: c
Explanation: Unit volume is not a parameter to determine the efficiency of the turbine. Power of a turbine is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
6. Which among the following control the flow rate?
a) Valve
b) Pump
c) Head
d) Tank pipe
Answer: a
Explanation: Flow rate of the tank is controlled by the valve. The actuation of individual valve closes. This corresponds to the set of nozzle thereby controlling the actual flow rate of the fluid passing through the valve.
7. The advantage of nozzle governing is that no regulating pressure is applied.
a) True
b) False
Answer: a
Explanation: The advantage of nozzle governing is that no regulating pressure is applied. The actuation of individual valve closes the corresponding set of nozzle. Thus, controlling the flow rate.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
Answer: b
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. When do we apply by pass governing?
a) When turbine is overloaded
b) When Unit speed decreases
c) When Unit power increases
d) When Unit pressure decreases
Answer: a
Explanation: The main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations. This happens occasionally in the working of the turbine. During this, a bypass valve is used.
10. When bypass valve is opened to _______
a) Increase Pressure
b) Increase Unit speed
c) Increase Unit power
d) Increase the amount of fresh steam
Answer: d
Explanation: When a by pass valve is opened, a fresh steam is introduced into the turbine, thereby increasing the amount of fresh steam. The main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations.
11. What is the unit of steam rate?
a) kg
b) kg/m
c) kg/kWh
d) N/m
Answer: c
Explanation: The unit of stream is equal to kg/kWh. In the process of throttle governing, it is denoted by the symbol ‘a’. The variation of the steam consumption rate with the turbine load during governing is linear.
12. With the increase in load, Energy in the turbine ________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. Combination governing involves usage of two or more governing.
a) True
b) False
Answer: a
Explanation: Yes, Combination governing involves usage of two or more governing. Most usage is the by pass and the nozzle governing as they tend to match the load on the turbine. Thus, increasing its efficiency.
14. When the mechanical speed of the shaft increases beyond 110 percent, we use _________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the mechanical speed of the shaft increases beyond 110 percent, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Centrifugal Pumps”.
1. Centrifugal pump is a_________
a) Turbomachinery
b) Flow regulating device
c) Drafting device
d) Intercooling device
Answer: a
Explanation: Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
2. Turbomachines work under ________
a) Newtons first law
b) Newtons second law
c) Newtons third law
d) Kepler’s law
Answer: b
Explanation: Turbomachines work under Newtons second law. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
3. The main function of nozzle is to __________
a) Varying temperatures
b) Pressure variations
c) Load variations
d) Heat variations
Answer: b
Explanation: The main function of nozzle is to vary the pressure of fluid passing through the nozzle. It is done by opening and shutting the sets of nozzles. Thus, its main function is to regulate pressure of the fluid.
4. The main function of centrifugal pumps are to ________
a) Transfer speed
b) Transfer pressure
c) Transfer temperature
d) Transfer energy
Answer: d
Explanation: The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
5. Centrifugal pumps transfer energy from _______
a) Rotor to fluid
b) Fluid to rotor
c) Draft to rotor
d) Rotor to draft
Answer: a
Explanation: Centrifugal pumps transfer energy from rotor to fluid. The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery.
6. Which among the following control the flow rate?
a) Valve
b) Pump
c) Head
d) Tank pipe
Answer: a
Explanation: Flow rate of the tank is controlled by the valve. The actuation of individual valve closes. This corresponds to the set of nozzle thereby controlling the actual flow rate of the fluid passing through the valve.
7. Turbines and compressors work with the gas, while centrifugal pump transfers energy.
a) True
b) False
Answer: a
Explanation: Turbines and compressors work with the gas, while centrifugal pump transfers energy. Centrifugal pumps transfer energy from rotor to fluid. The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
Answer: b
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.
a) True
b) False
Answer: a
Explanation: The statement is true. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery. The main function of centrifugal pumps are to transfer energy.
10. Centrifugal pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid
Answer: d
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.
11. Centrifugal pumps transport fluids by converting _________
a) Kinetic energy to hydrodynamic energy
b) Hydrodynamic energy to kinetic energy
c) Mechanical energy to kinetic energy
d) Mechanical energy to Hydrodynamic energy
Answer: a
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy.
12. With the increase in load, Energy in the turbine________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. The rotational kinetic energy comes from ______
a) Engine motor
b) Pump
c) Tank
d) Draft tube
Answer: a
Explanation: Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. The rotational kinetic energy comes from engine or electrical motor.
14. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. The fluid coming into the centrifugal pump is accelerated by ________
a) Throttle
b) Impeller
c) Nozzle
d) Governor
Answer: b
Explanation: The fluid coming into the centrifugal pump is accelerated by an impeller. The fluid enters the pump along a radially outward direction into the diffuser or a volute chamber.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Main Parts of Centrifugal Pumps”.
1. A gear pump uses ___________
a) Petrochemical pumps
b) Meshing of gears
c) Froth pumps
d) Airlift pumps
Answer: b
Explanation: A gear pump uses meshing of gears. This meshing is done to pump fluid by displacement. Gear pumps are widely used in chemical installations.
2. The fundamental significance of all the turbomachinery is _______
a) Conservation of momentum
b) Conservation of mass
c) Conservation of heat
d) Conservation of speed
Answer: a
Explanation: The fundamental significance of all the turbomachinery is the conservation of momentum. It plays an important role in various turbomachinery.
3. The most common pump used for hydraulic fluid power application is __________
a) Centrifugal pumps
b) Gear pump
c) Froth pumps
d) Airlift pumps
Answer: b
Explanation: The most common pump used for hydraulic fluid power application is gear pump. A gear pump uses meshing of gears. This meshing is done to pump fluid by displacement. Gear pumps are widely used in chemical installations.
4. The change of angular momentum in a pump is equal to the _________
a) Sum of speeds
b) Sum of individual momentum
c) Sum of temperatures
d) Sum of energy transferred from a body
Answer: b
Explanation: The change of angular momentum in a pump is equal to the sum of individual momentum.
5. Conservation of angular momentum is described by _______
a) Newtons equation
b) Euler’s equation
c) Rutherford’s equation
d) Maxim equation
Answer: b
Explanation: Conservation of angular momentum is described by Euler’s equation. It states that the change of angular momentum in a pump is equal to the sum of individual momentum.
6. Gear pumps are mainly used in chemical installations because they pump ________
a) High viscosity fluids
b) High density fluids
c) High pressure fluids
d) High temperature fluids
Answer: a
Explanation: Gear pumps are mainly used in chemical installations because they pump high viscosity fluids. They use two external spur gears for this purpose.
7. Gear pumps convert rotational kinetic energy to hydrodynamic energy.
a) True
b) False
Answer: a
Explanation: Gear pumps are used to transport fluids. They transport fluids by conversion of energies. Gear pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy.
8. The inlet passage of centrifugal pump is controlled by ________
a) Gate
b) Head race
c) Turbine
d) Pump
Answer: a
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. Absolute exit velocity in a pump is denoted as ______
a) c2
b) v2
c) p2
d) w2
Answer: a
Explanation: Absolute exit velocity in a pump is denoted as ‘c2’.
10. Gear pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid
Answer: d
Explanation: Gear pumps are used to transport fluids. They transport fluids by conversion of energies. A gear pump uses meshing of gears. This meshing is done to pump fluid by displacement. Gear pumps are widely used in chemical installations.
11. Vertical Centrifugal pumps are also called as _________
a) Cantilever pumps
b) Hydrodynamic pump
c) Mechanical pump
d) Hydroelectric pump
Answer: a
Explanation: Vertical Centrifugal pumps are also called as cantilever pumps.
12. With the increase in load, Energy in the turbine________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. The rotational kinetic energy comes from ______
a) Engine motor
b) Pump
c) Tank
d) Draft tube
Answer: a
Explanation: Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. The rotational kinetic energy comes from engine or electrical motor.
14. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. Gear pumps are ___________
a) Tangential flow pumps
b) Positive displacement pumps
c) Negative displacement pumps
d) Radial pumps
Answer: a
Explanation: Gear pumps are positive displacement pumps or fixed displacement pumps. This means that they pump at a constant amount of fluid each revolution.
This set of Hydraulic Machines MCQs focuses on “Work done by Centrifugal Pump”.
1. The fluid gains _________ while passing through the impeller.
a) Velocity
b) Pressure
c) Temperature
d) Velocity and pressure
Answer: d
Explanation: The fluid gains both velocity and pressure while passing through the impeller. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors.
2. What is the shape of the diffuser in the centrifugal pump?
a) Round
b) Dough nut
c) Rectangle
d) Cylindrical
Answer: b
Explanation: The shape of the diffuser passing present in the centrifugal pump is doughnut shaped. It is made into that shape as it allows the device to scroll up and down. Due to this, the casing decelerates the flow.
3. When the casing in a centrifugal pump decelerates the flow, what increases?
a) Pressure
b) Temperature
c) Volume
d) Flow rate
Answer: a
Explanation: When the casing in a centrifugal pump decelerates the flow, pressure in the turbine increases. The diffuser helps this happen. The shape of the diffuser passing present in the centrifugal pump is doughnut shaped.
4. The velocity imparted by the impeller is converted into _________
a) Pressure energy
b) Kinetic energy
c) Momentum
d) Potential energy
Answer: a
Explanation: The velocity imparted by the impeller is converted into pressure energy. It is in accordance with the Newtons second law.
5. The consequence of Newtons second law is_________
a) Conservation of angular momentum
b) Conservation of mass
c) Conservation of potential energy
d) Conservation of kinetic energy
Answer: a
Explanation: The consequence of Newtons second law is the conservation of angular momentum. This, in accordance with newtons second law, provides the basic details to define parameters in the centrifugal pump.
6. Change of angular momentum is equal to ________
a) Sum of external moments
b) Sum of their potential energies
c) Sum of their kinetic energies
d) Sum of their pressures
Answer: a
Explanation: Change of angular momentum is equal to Sum of external moments. This is in accordance with Newtons second law. The consequence of Newtons second law is the conservation of angular momentum.
7. Euler developed the head pressure equation in centrifugal pumps.
a) True
b) False
Answer: a
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. Euler developed the head pressure equation in centrifugal pumps.
8. What is a major advantage of centrifugal pump?
a) Cost
b) Simple in construction
c) Efficiency
d) Pump parameters
Answer: b
Explanation: The major advantage of the centrifugal pump is that it has got a simple construction when compared to other types of centrifugal pumps.
9. ‘Ht’ means _______
a) Tangential head
b) Horizontally head
c) Theory head pressure
d) Radially head pressure
Answer: c
Explanation: ‘Ht’ in the context of centrifugal pump means theory head pressure. It is used in a centrifugal pump equation that was derived by Euler. Euler developed the head pressure equation in centrifugal pumps.
10. Centrifugal pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid
Answer: d
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.
11. Different velocities in a centrifugal pump are determined by using ________
a) Velocity triangle
b) Reynolds number
c) Froude number
d) Overall efficiency
Answer: a
Explanation: Different velocities in a centrifugal pump are determined by using velocity triangle. This is an important triangle that determines the way the pump works.
12. Due to its impeller action, centrifugal pumps can cover a wide range of fluid pump applications.
a) True
b) False
Answer: a
Explanation: Due to its impeller action, centrifugal pumps can cover a wide range of fluid pump applications. Thus, the impeller action plays an important role.
13. With the increase in the input power, efficiency _______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: With the increase in the input power, efficiency decreases. As the input power is inversely proportional to the efficiency of the pump.
14. What is unit of standard acceleration?
a) kg/m
b) kg/s
c) kg/m 3
d) N/m
Answer: c
Explanation: The unit of standard acceleration of the centrifugal pump is kg/m 3 . It is denoted as g. It is also called as the acceleration due to gravity.
15. What does PSP stand for?
a) Pump start procedure
b) Positive start pump
c) Pump start pointer
d) Positive start pointer
Answer: a
Explanation: PSP stands for Pump start procedure. It is the basic method to start the pump by lining up the pump valves in a sequence by ensuring that the drain valve is closed.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Heads and Efficiencies in Centrifugal Pumps”.
1. What is the unit of flow rate?
a) kg.m
b) kg/m
c) m3/s
d) /s
Answer: c
Explanation: The unit of flow rate in a centrifugal pump is m3/s. It is denoted as ‘Q’. It plays an important role to determine the efficiency of the pump.
2. With the increase in the flow rate, efficiency ______
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: b
Explanation: With the increase in the flow rate, efficiency increases. The unit of flow rate in a centrifugal pump is m3/s. It is denoted as ‘Q’. It plays an important role to determine the efficiency of the pump.
3. Pump efficiency is defined as the ratio of ___________
a) Pressure to temperature
b) Temperature to pressure
c) Water horsepower to pump horsepower
d) Pump horse power to water horse power
Answer: c
Explanation: Pump efficiency is defined as the ratio of water horsepower to the pump horsepower. The unit of flow rate in a centrifugal pump is m3/s. It is denoted as ‘Q’. It plays an important role to determine the efficiency of the pump.
4. The difference in the total head of the pump is called _______
a) Manometric head
b) Euler head
c) Pressure head
d) Shaft head
Answer: a
Explanation: The difference in the total head of the pump is called manometric head. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors.
5. The ratio of manometric head to the work head is called _______
a) Manometric head
b) Euler head
c) Pressure head
d) Shaft head
Answer: b
Explanation: The ratio of manometric head to the work head is called Euler head. It is also called as manometric efficiency.
6. What is the unit of energy head?
a) m
b) m/s
c) m3/s
d) /s
Answer: a
Explanation: The unit of energy head is meter. The energy head is denoted as ‘H’. It plays an important role to determine the efficiency of the pump.
7. With the increase in energy head, efficiency ________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: b
Explanation: With the increase in energy head, efficiency increases. Since energy is directly proportional to the efficiency of the turbine. The unit of energy head is meter. The energy head is denoted as ‘H’. It plays an important role to determine the efficiency of the pump.
8. The head added by the pump is a sum of _________
a) Pressure
b) Static lift
c) Volume
d) Flow rate
Answer: b
Explanation: The head added by the pump is a sum of static lift. With the increase in energy head, efficiency increases. Since energy is directly proportional to the efficiency of the turbine. The unit of energy head is meter. The energy head is denoted as ‘H’. It plays an important role to determine the efficiency of the pump.
9. Power is most commonly expressed as ________
a) m
b) kW
c) m3/s
d) /s
Answer: b
Explanation: Power is most commonly expressed as kilo watts. One kilo watts is equal to 0.746 horse power. It plays an important role in determining the efficiency of the turbine.
10. PHE stands for __________
a) Pump Hydraulic efficiency
b) Pressure Hydraulic efficiency
c) Power Hydraulic efficiency
d) Pump hydraulic engine
Answer: a
Explanation: PHE stands for Pump hydraulic efficiency. Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies.
11. Vertical centrifugal pumps are also called as cantilever pumps.
a) True
b) False
Answer: a
Explanation: Vertical centrifugal pumps are also called as cantilever pumps. Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.
12. With increase in power, the efficiency_________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: With the increase in the input power, efficiency decreases. As the input power is inversely proportional to the efficiency of the pump.
13. Vertical pumps utilize unique shaft and bearing support configuration.
a) True
b) False
Answer: a
Explanation: Vertical pumps utilize unique shaft and bearing support configuration. It allows them to hang in the sump while the bearings are outside the sump. Thus, it is a true.
14. Which among the following is used in mineral industries?
a) Vertical pumps
b) Horizontal pumps
c) Froth pumps
d) Multistage pumps
Answer: c
Explanation: In the mineral industries, we use froth pumps to extract oil sand. Froth is generated to separate rich minerals.
This set of Hydraulic Machines Questions and Answers for Aptitude test focuses on “Minimum Speed for Starting Centrifugal Pump”.
1. Vertical centrifugal pumps are also called as ________
a) Froth pumps
b) Multistage pumps
c) Cantilever pumps
d) Magnetic pumps
Answer: c
Explanation: Vertical centrifugal pumps are also called as cantilever pumps. They utilize a unique shaft and bearing support for configuration. Thus, it is called as cantilever pumps.
2. Vertical pump uses _______
a) Draft tube
b) Throttle bush
c) Stuffing box
d) Interlining
Answer: b
Explanation: Vertical pumps use throttle bush. They do not use stuffing box. Vertical centrifugal pumps are also called as cantilever pumps. They utilize a unique shaft and bearing support for configuration. Thus, it is called as cantilever pumps.
3. When the casing in a centrifugal pump decelerates the flow, what increases?
a) Pressure
b) Temperature
c) Volume
d) Flow rate
Answer: a
Explanation: When the casing in a centrifugal pump decelerates the flow, pressure in the turbine increases. The diffuser helps this happen. The shape of the diffuser passing present in the centrifugal pump is doughnut shaped.
4. The maximum volumetric efficiency of a pump is ________
a) 60%
b) 70%
c) 80%
d) 90%
Answer: d
Explanation: The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
5. The most common application of vertical centrifugal pump is used in _______
a) Parts washer
b) Mineral industry
c) Paper plating
d) Jukebox
Answer: a
Explanation: The most application of the vertical centrifugal pump is used in parts washer. Vertical pumps use throttle bush. They do not use stuffing box. Vertical centrifugal pumps are also called as cantilever pumps.
6. What does BEP stand for?
a) Best efficiency point
b) Brake ejection point
c) Break effect point
d) Best effect point
Answer: a
Explanation: BEP stands for Best efficient point. It is a point at which Shut off and Run out point. It helps to identify the pumps performance.
7. The height of a column in a pump is called as _______
a) Vertical head
b) Horizontal head
c) Static head
d) Multi head
Answer: c
Explanation: In a centrifugal pump, the height of the column is called as a static head. Static head corresponds to the pressure depending on the weight.
8. The centrifugal pump has varying flow depending on the _________
a) Pressure
b) Static lift
c) Volume
d) Flow rate
Answer: a
Explanation: Due to pressure variations there are changes that take place in the centrifugal pump. Thus, the flow keeps varying.
9. What is purpose of froth in froth pumps?
a) Separates rich minerals
b) Mixes rich minerals
c) Removes ores
d) Detects oil
Answer: a
Explanation: The main function of the froth in froth pumps is to separate rich minerals. It is also used to separate bitumen from the sand and the clays.
10. Froth contains air that blocks the pumps.
a) True
b) False
Answer: a
Explanation: Froth contains air that blocks the pumps. The main function of the froth in froth pumps is to separate rich minerals. It is also used to separate bitumen from the sand and the clays.
11. When froth blocks the pump, it leads to _______
a) Separation of rich minerals
b) Mixing of rich minerals
c) Removing of ores
d) Loss of prime
Answer: d
Explanation: When froth blocks the pump, it leads to loss of prime. The main function of the froth in froth pumps is to separate rich minerals. It is also used to separate bitumen from the sand and the clays.
12. What affects volumetric efficiency of the pump?
a) Complex interactions
b) Internal interactions
c) Retain flow
d) Air flow
Answer: a
Explanation: The volumetric efficiency of the centrifugal is affected due to complex interactions. Thus, some engines use two intake manifolds.
13. The Positive Displacement Pump has more or less a constant flow regardless of the system pressure or head.
a) True
b) False
Answer: a
Explanation: The Positive Displacement Pump has more or less a constant flow regardless of the system pressure or head.
14. What is the purpose of inducer in a froth pump?
a) It recirculates air
b) The pressurizes the air
c) Froths are generated
d) It breaks the bubbles
Answer: d
Explanation: The purpose of the inducer in a froth pump is to break the bubbles. The main function of the froth in froth pumps is to separate rich minerals. It is also used to separate bitumen from the sand and the clays.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Multistage Centrifugal Pumps for High Heads”.
1. A multistage centrifugal pumps has more than two _______
a) Pumps
b) Impellers
c) Turbines
d) Magnetic pumps
Answer: b
Explanation: A multistage centrifugal pumps has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
2. The impeller is mounted on a ________
a) Draft tube
b) Throttle bush
c) Stuffing box
d) Shaft
Answer: d
Explanation: The impeller is mounted on one shaft or different shaft. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
3. At each stage the fluid is directed ________
a) Towards the centre
b) Away the centre
c) Towards the surface
d) Away from the centre
Answer: a
Explanation: At each stage in the centrifugal pump, the fluid is directed to towards the centre. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
4. If the cylinder is filled with fuel or air it is said to be ___________
a) 100% efficient
b) Transfer efficient
c) Nil efficient
d) Flow effective
Answer: a
Explanation: If the cylinder is filled with fuel or air, it is said to be 100 percent efficient. It plays a major role in regulating the flow of fluid.
5. SOH in a pump stands for_______
a) Shut Off head
b) Shut off heat
c) Shut off hybrid
d) Set off head
Answer: a
Explanation: SOH in a pump stands for Shut OFF head. The shut off head is located at the maximum head of the pipe.
6. At higher pressures, the impeller is connected in _______
a) Series
b) Parallel
c) Equilibrium
d) Series and parallel
Answer: a
Explanation: At higher pressures, the impeller is connected in series. The impeller is mounted on one shaft or different shaft. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
7. When the flow output is higher, impellers are connected in________
a) Series
b) Parallel
c) Equilibrium
d) Series and parallel
Answer: b
Explanation: When the flow output is higher, impellers are connected in parallel. The impeller is mounted on one shaft or different shaft. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
8. The point at which piping system controls the flow rate is called ______
a) Pressure point
b) Static lift
c) Operating point
d) Flow point
Answer: c
Explanation: The point at which piping system controls the flow rate is called operating point of the pump. It plays a major role in controlling the piping system before regulation.
9. What is the common application of multistage centrifugal pump?
a) Mineral industries
b) Boiler feed water pump
c) Removes ores
d) Detects oil
Answer: b
Explanation: The most common application of multistage centrifugal pump is boiler feed water pump.
10. A multistage centrifugal pump produces a pressure of __________
a) 10 Pa
b) 100 MPa
c) 21 MPa
d) 150 MPa
Answer: c
Explanation: A multistage centrifugal pump produces a pressure of 21 MPa. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
11. All energy that is transferred from the fluid is derived from ________
a) Electrical energy
b) Mechanical energy
c) Thermal energy
d) Chemical energy
Answer: b
Explanation: All energy that is transferred from the fluid is derived from Mechanical energy. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
12. The point at which the centrifugal pump operates at maximum efficiency is called _______
a) Duty point
b) Flow point
c) Static point
d) Operating point
Answer: a
Explanation: The point at which the centrifugal pump operates at maximum efficiency is called duty point. It is determined by the flow rate of the pump.
13. The energy transferred can be measured by isentropic compression.
a) True
b) False
Answer: a
Explanation: The energy transferred in a centrifugal pump can be measured by isentropic compression. The multistage centrifugal is similar to the centrifugal pumps working.
14. What does TDH stand for?
a) Total dynamic head
b) Total depth head
c) Tight drum head
d) Target dynamic head
Answer: a
Explanation: TDH stands for total dynamic head. It is total height at which fluid is to be pumped for maximum effiency.
15. The mechanical energy is developed by the impeller.
a) True
b) False
Answer: a
Explanation: The mechanical energy is developed by the impeller. The energy transferred in a centrifugal pump can be measured by isentropic compression. The multistage centrifugal is similar to the centrifugal pumps working. Thus, it is true.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Multistage Centrifugal Pumps for High Discharge”.
1. The mechanical energy can be measured by ______
a) Adiabatic expansion
b) Isentropic compression
c) Adiabatic compression
d) Isentropic expansion
Answer: b
Explanation: The mechanical energy in a centrifugal pump that is driven by the impeller mounted on a shaft is measured by isentropic compression. Thus, the correct choice is isentropic compression.
2. How many impellers does a multistage centrifugal pump have?
a) Zero
b) One
c) Exactly two
d) Two and more
Answer: d
Explanation: The centrifugal pump consists of two or more impellers. The impeller is mounted on one shaft or different shaft. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
3. The energy usage in pumping installation is determined by _______
a) Friction characteristics
b) Pipe diameter
c) Surface tension
d) Thermal expansion
Answer: a
Explanation: At each stage in the centrifugal pump, the fluid is directed to towards the centre. The energy usage in pumping installation is determined by Friction characteristics. Thus, it is the most suitable option.
4. Which among the following is a friction factor?
a) Newtons factor
b) Darcy’s factor
c) Transfer temperature
d) Heizenberg’s factor
Answer: b
Explanation: From the above, the factor that involves friction is determined by Darcy’s friction factor. The energy usage in pumping installation is determined by Friction characteristics. Thus, it is used in energy calculations in a pump.
5. What is the dimension for Darcy’s friction factor?
a) kg/m
b) N/mm
c) kg
d) Dimensionless
Answer: d
Explanation: Darcy’s friction factor is dimensionless. It is one of the major applications in Fluid dynamics. The energy usage in pumping installation is determined by Friction characteristics. Thus, it is dimensionless.
6. Formation of bubbles in an impeller is called ______
a) Cavities
b) Defects
c) Friction
d) Heat burn
Answer: a
Explanation: Formation of bubbles in an impeller is called as its as its cavities. These cavities develop intense shockwaves in the impeller.
7. Centrifugal pump works by imparting _______
a) Potential energy
b) Kinetic energy
c) Heat energy
d) Electrical energy
Answer: b
Explanation: Centrifugal pump works by imparting kinetic energy to the liquid for rotating the impeller rotor.
8. What is the full form of NPSH in a pump?
a) Net pressure suction head
b) Net positive suction head
c) Non-pressure suction head
d) Net pressure super head
Answer: b
Explanation: The full form of NPSH is Net positive suction head. The head added by the pump is a sum of static lift. Thus, corresponds to the efficient working of the pump. Higher the NPSH, more efficient the pump is.
9. When the NPSH is low, it leads to ________
a) Breaking
b) Wear
c) Corrosion
d) Cavitation
Answer: d
Explanation: When the NPSH is low, it leads to cavitation. Cavitation is one of the major drawbacks that are seen in a centrifugal pump. There are various other problems as well. But, cavitation is due to low NPSH.
10. Wear of impeller can be worsened by __________
a) Draft tube
b) Pump pressure
c) Suspended solenoids
d) Turbine head
Answer: c
Explanation: Wear of impeller can be worsened by suspended solenoids. Wear and tear is one of the major drawbacks that are seen in a centrifugal pump. It affects the working of the impeller, thus resulting in an inefficient working.
11. Which pump is the most efficient centrifugal pump?
a) Electrical pump
b) Reciprocating pump
c) Heat pump
d) Pressure pump
Answer: b
Explanation: Reciprocating pump is the most efficient centrifugal pump because as the pressure increases, the flow rate remains constant.
12. Corrosion in the pump is developed due to _______
a) Pressure of air
b) Fluid properties
c) Draft tube
d) Tank dimensions
Answer: b
Explanation: Corrosion in the pump is developed due to fluid properties. The flow of fluid plays a major role in determining the corrosion developed. Fluid flow can broadly be classified into laminar and turbulent depending on its Reynolds number.
13. Over heating is a major problem faced in a pump.
a) True
b) False
Answer: a
Explanation: Over heating is a major problem faced in a pump. The temperature in a centrifugal pump is increases mainly due to the presence of low flow. Thus, by heating the fluid, the velocity of fluid flow increases.
14. What is the effect of cavitation in boat propeller?
a) It recirculates air
b) The pressurizes the air
c) It leads to fast spinning
d) It breaks the bubbles
Answer: c
Explanation: Cavitation in a boat propeller or a ship propeller leads to fast spinning due to the formation of bubbles.
15. Lack of prime is a problem faced in centrifugal pump.
a) True
b) False
Answer: a
Explanation: Yes, Lack of prime is a problem faced in centrifugal pump. It means that the centrifugal pump must be filled in order to operate in an effective way. The fluid must be filled in such a way so that it can pump.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Specific Speed Centrifugal Pumps”.
1. The energy usage of a pump is determined by _______
a) Adiabatic expansion
b) Power required
c) Adiabatic compression
d) Isentropic expansion
Answer: b
Explanation: The energy usage of a pump is determined by power required. Thus, it plays an important role in determining the amount of energy that a pump dissipates during its operation. It is with respect to the length of time.
2. For an oil field to have solid control, it needs _______
a) Draft tubes
b) Throttle bush
c) Stuffing box
d) Centrifugal pumps
Answer: d
Explanation: For an oil field to have solid control, it needs centrifugal pumps. At each stage in the centrifugal pump, the fluid is directed to towards the centre. This makes it more efficient in operating a large oil field.
3. If we lower the temperature, the water pump cavitation ________
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: If we lower the temperature, the water pump cavitation decreases. This happens as the NPSH value reaches a safety margin.
4. Which among the following is not a centrifugal pump?
a) Sand pumps
b) Froth pumps
c) Slurry pumps
d) Energy pumps
Answer: d
Explanation: From the above, Energy pumps are not a type of centrifugal pump. At each stage in the centrifugal pump, the fluid is directed to towards the centre. The energy usage in pumping installation is determined by Friction characteristics. Thus, it is not a suitable option.
5. Centrifugal pumps work under the same principle, but differ in their _______
a) Working
b) Functions
c) Dimensions
d) Impeller
Answer: b
Explanation: Centrifugal pumps work under the same principle, but differ in their functions. At each stage in the centrifugal pump, the fluid is directed to towards the centre. The energy usage in pumping installation is determined by Friction characteristics.
6. If we raise the liquid level in the suction vessel, cavitation ______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: If we raise the liquid level in the suction vessel, cavitation decreases. This happens as the NPSH value reaches a safety margin.
7. Magnetic coupled pumps are also called as _________
a) Series pumps
b) Parallel pumps
c) Froth pumps
d) Drive pumps
Answer: d
Explanation: Magnetic coupled pumps are also called a magnetic drive pumps. They show a lot of difference in their traditional pumping style. It is connected by means of direct mechanical shaft.
8. Magnetic coupled pumps works via ________
a) Antiferromagnet
b) Drive magnet
c) Pump magnet
d) Ferromagnet
Answer: b
Explanation: Magnetic coupled pumps works via drive magnet. Magnetic coupled pumps are also called a magnetic drive pumps. They show a lot of difference in their traditional pumping style. It is connected by means of direct mechanical shaft.
9. When we change the pump, the cavitation ______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: By changing the pump we can decrease the cavitation in the pump by bringing the NPSH value to a safety margin.
10. If we reduce the motor rpm in an impeller, cavitation _______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: If we reduce the motor rpm in an impeller, cavitation decreases. This can be done by setting the NPSH value in the safety limit.
11. Decreasing the diameter of the eye of the impeller, cavitation _________
a) Increases
b) Decreases
c) Same
d) Independent
Answer: a
Explanation: Decreasing the diameter of the eye of the impeller, cavitation increases due to deviation from the safety limit.
12. No gland is needed for the centrifugal pump.
a) True
b) False
Answer: a
Explanation: No gland is needed for the centrifugal pump. This is because they have no direct connection between the motor shaft and the impeller, so there is not a requirement of gland in pumps.
13. Pump is always supported by bearings.
a) True
b) False
Answer: b
Explanation: Pump shaft is not always supported by bearings. Since the pumps have no bearing support. The pumps are provided with a housing. The inner walls of the pump are provided with bushings.
14. If we use an impeller inducer, we can reduce the cavitation in a centrifugal pump.
a) True
b) False
Answer: a
Explanation: Yes, If we use an impeller inducer, we can reduce the cavitation in a centrifugal pump by bringing the NPSH value to a safety limit.
15. There will be leakage only if there is ________
a) High pressure
b) High temperature
c) Froths are generated
d) Casing breakage
Answer: d
Explanation: Pumps have a major problem called as leakage. This might lead to a lot of losses during product manufacture. Thus, the leakage is mainly due to the breaking of the case. Thus, the correct option is casing breakage.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Priming Centrifugal Pumps”.
1. When a pump casing is filled with liquid before it is started, it is called as _________
a) Adiabatic expansion
b) Priming
c) Adiabatic compression
d) Isentropic expansion
Answer: b
Explanation: When a pump casing is filled with liquid before it is started, it is called as priming. Most of the centrifugal pumps are not self priming. At this stage, the pump will not be able to function.
2. The pump will become incapable of pumping in case of _______
a) Gas bounding
b) Throttle bush
c) Stuffing box
d) Casing breakage
Answer: d
Explanation: For an oil field to have solid control, it needs centrifugal pumps. At each stage in the centrifugal pump, the fluid is directed to towards the centre. This makes it more efficient in operating a large oil field.
3. Priming is needed when impeller cannot impart enough _________
a) Draft speed
b) Energy
c) Pressure
d) Heat
Answer: b
Explanation: Priming is needed when impeller cannot impart enough energy. Therefore priming is compulsory in this case.
4. Priming performs response using ________
a) Stimulus
b) Froth
c) Slurry
d) Heat
Answer: a
Explanation: Priming performs response using a stimulus. It is an implicit method in which exposure to flow of fluid takes place.
5. To avoid gas bounding, the pump is _________
a) Heated
b) Elevated
c) Primed
d) Charged
Answer: c
Explanation: Centrifugal pumps work under the same principle, but differ in their functions. At each stage in the centrifugal pump, the fluid is directed to towards the centre. To avoid gas bounding, the pump is primed.
6. Centrifugal pumps are located ________ the level of source
a) Below
b) Above
c) Parallel with
d) Series with
Answer: a
Explanation: Centrifugal pumps are located below the level of source. It is located in such way because, it takes away the suction at a faster rate.
7. A pump that can evacuate air is called as _________
a) Series pumps
b) Self priming pumps
c) Froth pumps
d) Drive pumps
Answer: b
Explanation: A pump that can evacuate air is called as self priming pumps. In normal conditions, it is difficult for centrifugal pumps to evacuate the air from the inlet line leading to a fluid level to a different altitude.
8. What does CPO stand for?
a) Centrifugal pump operation
b) Centrifugal part operation
c) Centrifugal pump output
d) Centrifugal part output
Answer: a
Explanation: CPO stands for centrifugal pump operation. It has got a pump start off procedure and pump shut down procedure.
9. Self priming pumps overshadow the function of __________
a) Self auxiliary device
b) Wear rate
c) Corrosion device
d) Cavitation device
Answer: a
Explanation: Self priming pumps overshadow the function of self auxiliary device. A pump that can evacuate air is called as self priming pumps. In normal conditions, it is difficult for centrifugal pumps to evacuate the air from the inlet line leading to a fluid level to a different altitude.
10. What is necessary for self priming to take place?
a) Draft tube
b) Pump casing
c) Suspended solenoids
d) Turbine head
Answer: b
Explanation: For self priming to take place, pump casing is necessary. This helps to evacuate air in normal conditions.
11. Centrifugal pumps with an internal suction stage are called as _________
a) Series pumps
b) Self priming pumps
c) Froth pumps
d) Drive pumps
Answer: b
Explanation: Centrifugal pumps with an internal suction stage are called as self priming pumps. A pump that can evacuate air is called as self priming pumps. In normal conditions, it is difficult for centrifugal pumps to evacuate the air from the inlet line leading to a fluid level to a different altitude.
12. Two phase mixture is pumped unit the suction line is evacuated.
a) True
b) False
Answer: a
Explanation: Two phase mixture is pumped unit the suction line is evacuated as the pump operates without a foot valve and without an evacuation device on the suction side. The pump has to be primed for this purpose.
13. During normal working operation, the pump works like __________
a) Centrifugal pumps
b) Self priming pumps
c) Froth pumps
d) Drive pumps
Answer: a
Explanation: Pump shaft is not always supported by bearings. Since the pumps have no bearing support. The pumps are provided with a housing. During normal working operation, the pump works like centrifugal pumps.
14. The pump function that works on rinsing is called as dialysis of pump.
a) True
b) False
Answer: a
Explanation: Yes, The pump function that works on rinsing is called as dialysis of pump.
15. What is purpose of vent valve in a pump?
a) High pressure control
b) High temperature control
c) Froths are generated can be minimized
d) To prevent siphon action
Answer: d
Explanation: The main function of a suction swindle valve or vent valve in a centrifugal pump is to prevent any siphon action and ensure that the fluid remains in the casing when the pump has been stopped.
This set of Hydraulic Machines Questions and Answers for Campus interviews focuses on “Net Positive Suction Head – NPSH”.
1. In hydraulic head, NPSH is used for the analysis of __________
a) Adiabatic expansion
b) Priming
c) Wear
d) Cavitation
Answer: d
Explanation: In hydraulic head, net positive circuit is used for the analysis of cavitation. It determines the cavitation present in the centrifugal pump by different methods.
2. NPSH is the difference between _______
a) Suction pressure and vapour pressure
b) Vapour pressure and suction pressure
c) Suction pressure and heat
d) Shaft and head
Answer: a
Explanation: NPSH is defined as the difference suction pressure and vapour pressure. It is called as the net positive suction head.
3. What can NPSH be used to determine _______
a) Friction characteristics
b) Pipe diameter
c) Cavitation
d) Thermal expansion
Answer: c
Explanation: NPSH is used to determine the cavitation in pumps. NPSH is defined as the difference suction pressure and vapour pressure. It is called as the net positive suction head.
4. The measure of how close the fluid is to the given point is called _________
a) Flashing
b) Darcy’s factor
c) Transfer temperature
d) Heizenberg’s factor
Answer: a
Explanation: The measure of how close the fluid is to the given point is called flashing. It is one of the major methods in the NPSH to determine the cavitation.
5. What is the dimension for Darcy’s friction factor?
a) kg/m
b) N/mm
c) kg
d) Dimensionless
Answer: d
Explanation: Darcy’s friction factor is dimensionless. It is one of the major applications in Fluid dynamics. The energy usage in pumping installation is determined by Friction characteristics. Thus, it is dimensionless.
6. NPSH is relevant ________
a) Outside the pumps
b) Inside the pumps
c) Away from the pumps
d) Series and parallel with the pumps
Answer: a
Explanation: NPSH is relevant inside the pumps. hydraulic head, net positive circuit is used for the analysis of cavitation. It determines the cavitation present in the centrifugal pump by different methods.
7. With the increase in cavitation, the drag coefficient of the impeller ______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: a
Explanation: With the increase in cavitation, the drag coefficient of the impeller increases. When the flow output is higher, impellers are connected in parallel. The impeller is mounted on one shaft or different shaft.
8. What is the full form of NPSH in a pump?
a) Net pressure suction head
b) Net positive suction head
c) Non-pressure suction head
d) Net pressure super head
Answer: b
Explanation: The full form of NPSH is Net positive suction head. The head added by the pump is a sum of static lift. Thus, corresponds to the efficient working of the pump. Higher the NPSH, more efficient the pump is.
9. When the NPSH is low, it leads to ________
a) Breaking
b) Wear
c) Corrosion
d) Cavitation
Answer: d
Explanation: When the NPSH is low, it leads to cavitation. Cavitation is one of the major drawbacks that are seen in a centrifugal pump. There are various other problems as well. But, cavitation is due to low NPSH.
10. What is positive suction head?
a) Draft tube is above
b) Pump pressure is above
c) Liquid level is above
d) Turbine head is above
Answer: c
Explanation: Positive suction head is defined as the point in which the liquid level is above the centre line of the pump.
11. NPSHr is determined by using ______
a) Pump pressure
b) PumpLinx
c) Heat transfer
d) Chemical energy
Answer: b
Explanation: NPSHr of a pump can be determined by using Pumplinx. The full form of NPSH is Net positive suction head. The head added by the pump is a sum of static lift.
12. Corrosion in the pump is developed due to _______
a) Pressure of air
b) Fluid properties
c) Draft tube
d) Tank dimensions
Answer: b
Explanation: Corrosion in the pump is developed due to fluid properties. The flow of fluid plays a major role in determining the corrosion developed. Fluid flow can broadly be classified into laminar and turbulent depending on its Reynolds number.
13. Calculation of NPSH in a turbine is different from the calculation of NPSH in a pump.
a) True
b) False
Answer: a
Explanation: Calculation of NPSH in a turbine is different from the calculation of NPSH in a pump. It is mainly because the point at which the cavitation will first occur is in a different place.
14. If we use two lower capacity pumps in parallel, cavitation ________
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: If we use two lower capacity pumps in parallel, cavitation decreases. It happens when the NPSh value is bought in its safety limit.
15. Vapour pressure is strongly dependent on temperature in a pump.
a) True
b) False
Answer: a
Explanation: Yes, Vapour pressure is strongly dependent on temperature in a pump. It will thus increase the net positive suction head of the centrifugal pump.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Main Characteristic Curves”.
1. The characteristic curves of a centrifugal pump, plots ______ required by the pump.
a) Velocity
b) Pressure
c) NPSH
d) Velocity and pressure
Answer: c
Explanation: The characteristic curves of a centrifugal pump, plots net positive suction head required by the pump. These curves play an important role in determining the efficiency of a centrifugal pump.
2. What is the shape of the diffuser in the centrifugal pump?
a) Round
b) Dough nut
c) Rectangle
d) Cylindrical
Answer: b
Explanation: The shape of the diffuser passing present in the centrifugal pump is doughnut shaped. It is made into that shape as it allows the device to scroll up and down. Due to this, the casing decelerates the flow.
3. When the casing in a centrifugal pump decelerates the flow, what increases?
a) Pressure
b) Temperature
c) Volume
d) Flow rate
Answer: a
Explanation: When the casing in a centrifugal pump decelerates the flow, pressure in the turbine increases. The diffuser helps this happen. The shape of the diffuser passing present in the centrifugal pump is doughnut shaped.
4. Which among the following is not a characteristic curve for centrifugal pump?
a) Transfer speed vs Transfer pressure
b) Head vs Flow rate
c) Power input vs pump efficiency
d) Specific speed vs pump efficiency
Answer: a
Explanation: The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery. Transfer speed vs Transfer pressure is not considered as a correct characteristic curve.
5. The consequence of Newtons second law is _________
a) Conservation of angular momentum
b) Conservation of mass
c) Conservation of potential energy
d) Conservation of kinetic energy
Answer: a
Explanation: The consequence of Newtons second law is the conservation of angular momentum. This, in accordance with newtons second law, provides the basic details to define parameters in the centrifugal pump.
6. Which of the following is taken into account during a characteristic curve?
a) Flow rate
b) Cavitation
c) Tolerances
d) Casing
Answer: a
Explanation: Flow rate is an important parameter that is taken into account for a characteristic curve. These curves play an important role in determining the efficiency of a centrifugal pump.
7. The normal operating range of centrifugal pump is sufficient to plot the characteristic curve.
a) True
b) False
Answer: a
Explanation: The normal operating range of centrifugal pump is sufficient to plot the characteristic curve. Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
Answer: b
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. As the specific speed increases, the slope of HQ curve _______
a) Decreases
b) Increases
c) Independent
d) Remains the same
Answer: c
Explanation: As the specific speed increases, the slope of HQ curve increases. It becomes steeper with the corresponding increase in the specific speed.
10. The primary selection tool is called as _______
a) Pump curve
b) Speed curve
c) Power curve
d) Fluid curve
Answer: a
Explanation: The primary selection tool is called as pump curve. It plays an essential role in determining efficiency.
11. In case of centrifugal turbines with low specific speed, the efficiency curve is _________
a) Pointed
b) Small
c) Steep
d) Flat
Answer: d
Explanation: In case of centrifugal turbines with low specific speed, the efficiency curve is relatively flat in the vertex. These curves play an essential role in determining the overall performance of the turbine.
12. In case of centrifugal turbines with high specific speed, the efficiency curve is
a) Pointed
b) Small
c) Steep
d) Flat
Answer: a
Explanation: In case of centrifugal turbines with high specific speed, the efficiency curve is relatively pointed in the vertex. These curves play an essential role in determining the overall performance of the turbine.
13. With the increase in the input power, efficiency _______
a) Increases
b) Decreases
c) Same
d) Independent
Answer: b
Explanation: With the increase in the input power, efficiency decreases. As the input power is inversely proportional to the efficiency of the pump.
14. What is unit of standard acceleration?
a) kg/m
b) kg/s
c) kg/m 3
d) N/m
Answer: c
Explanation: The unit of standard acceleration of the centrifugal pump is kg/m 3 . It is denoted as g. It is also called as the acceleration due to gravity. Thus, the correct option is ‘c’.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Effects and Precautions”.
1. The formation of vapour cavities is called _____
a) Static pressure drop
b) Cavitation
c) Isentropic expansion
d) Emulsion
Answer: b
Explanation: The formation of vapour cavities is called cavitation. It is formed due to the presence of small free liquids with different zones. These zones consists of different layers of forces acting on them.
2. What is the degree of reaction denoted as?
a) D
b) R
c) r
d) d
Answer: b
Explanation: Degree of reaction is defined as the ratio of the static pressure drop in the rotor to the static pressure drop in the stage. It can also be defined in the same way for enthalpy in different stages. It is denoted by the letter ‘R’.
3. Voids are created due to ______
a) Reaction ratio
b) Pressure ratio
c) Liquid free layers
d) Volumetric layers
Answer: c
Explanation: Voids in a turbine or pump is created due to the presence of liquid free layers. It is formed due to the presence of small free liquids with different zones. These zones consists of different layers of forces acting on them.
4. Cavitation usually occurs due to the changes in ________
a) Pressure
b) Temperature
c) Volume
d) Heat
Answer: a
Explanation: Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
5. Degree of reactions are most commonly used in ________
a) Turbomachinery
b) Pressure drag
c) Aerodynamics
d) Automobiles
Answer: a
Explanation: Degree of reaction is most commonly used in turbomachinery. Degree of reaction is defined as the ratio of the static pressure drop in the rotor to the static pressure drop in the stage. It can also be defined in the same way for enthalpy in different stages. It is denoted by the letter ‘R’.
6. At high pressure, the voids can generate ______
a) Drag force
b) Mass density
c) Shock waves
d) Flow speed
Answer: c
Explanation: At high pressure, the voids can generate shock waves. Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
7. Voids that implode near metal surface develops a_______
a) Drag force
b) Cyclic stress
c) Shock waves
d) Flow speed
Answer: b
Explanation: Voids that implode near metal surface develops a cyclic stress. This happens mainly due to repeated implosion of voids.
8. Internal cavitation occurs due to __________
a) Drag force
b) Cyclic stress
c) Shock waves
d) Flow speed
Answer: c
Explanation: At high pressure, the voids can generate shock waves. Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
9. Non- inertial cavitation is the one in which a bubble of fluid is forced to oscillate.
a) True
b) False
Answer: a
Explanation: Non- inertial cavitation is the one in which a bubble of fluid is forced to oscillate. It oscillates in a different size or shape due to some form of energy called the acoustic field.
10. The efficiency of the vane is given by _________
a) 1-V 2 2 / V 1 2
b) 1-(V 2 2 / V 1 2 )
c) V 2 2 / V 1 2
d) 1- V 1 2
Answer: a
Explanation: In a velocity triangle at the inlet and the outlet, the control volume is moving with a uniform velocity. Therefore, the momentum theorem of the control volume is at a steady flow. Thus, the efficiency of the vane is given by 1-(V 2 2 / V 1 2 ).
11. The velocities of the blade angles can be found out using ________
a) Mach number
b) Froude’s number
c) Velocity triangles
d) Reynolds number
Answer: c
Explanation: The velocity triangle represents various components. It mainly determines the velocities of fluids that act in a turbomachinery. It can be drawn for both inlet and outlet triangles with its angles.
12. Which among the following velocities cannot be found using the velocity triangle?
a) Tangential
b) Whirl
c) Relative
d) Parabolic
Answer: d
Explanation: The velocity triangle represents various components. It mainly determines the velocities of fluids that act in a turbomachinery. It can be drawn for both inlet and outlet triangles with its angles.
13. Hydrodynamic cavitation is due to the process of _________
a) Vaporisation
b) Sedimentation
c) Filtration
d) Excavation
Answer: a
Explanation: Hydrodynamic cavitation is due to the process of vaporisation. A bubble generation takes place in which implosion occurs during the flowing of liquid.
14. The process of bubble generation leads to __________
a) High temperatures
b) High pressures
c) High energy densities
d) High volumetric ratio
Answer: c
Explanation: The process of bubble generation leads to high energy densities. The local temperatures and local pressures at this point last for a very short time.
15. Super cavitation is the use of cavitation effect to create a bubble of steam inside a liquid.
a) True
b) False
Answer: a
Explanation: Yes, it is true. Super cavitation is the use of cavitation effect to create a bubble of steam inside a liquid. It is large to encompass an object passing through the liquid to reduce skin friction drag.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Reciprocating Pumps”.
1. Reciprocating pump is a ________
a) Negative displacement pump
b) Positive displacement pump
c) Diaphragm pump
d) Emulsion pump
Answer: b
Explanation: Reciprocation pump is a type of positive displacement pump. It has a piston pump, plunger and diaphragm. Reciprocating pumps have a good life provided that they are not left untouched.
2. What happens to the reciprocating pump when left untouched?
a) Efficiency decreases
b) Wear and tear
c) Surface expansion
d) Pressure change
Answer: c
Explanation: When left untouched over a period of time, the reciprocating pump undergoes wear and tear. Reciprocating pumps have a good life provided that they are not left untouched.
3. Reciprocating pumps operate by drawing ______ into the chamber
a) Liquid
b) Pressure
c) Heat
d) Electricity
Answer: a
Explanation: Reciprocating pumps operate by drawing liquid into the chamber or the cylinder with the help of a piston.
4. The cylinder of reciprocating cylinder is made up of _______
a) Cast iron
b) Wrought iron
c) Aluminium
d) Copper
Answer: a
Explanation: The cylinder of reciprocating cylinder is made up of cast iron. Sometimes it is also made of steel alloy. The movement of piston is obtained by a connecting rod which connects piston and rotating crank inside the cylinder.
5. The higher discharge valve line holds the discharge valve ________
a) Open
b) Closed
c) Stop functioning
d) Automatic
Answer: b
Explanation: The higher discharge valve line holds the discharge valve closed. This helps in maintaining the valve safely.
6. Reciprocating pumps are also called as __________
a) Force pumps
b) Mass Pumps
c) Heat pumps
d) Speed pumps
Answer: a
Explanation: Reciprocating pumps are also called as force pumps. It helps to lift the liquid by the help of a pressure and thus it is called as a force pump.
7. Reciprocating pumps are classified according to ___________
a) Drag force
b) Number of cylinders
c) Shock waves
d) Flow speed
Answer: b
Explanation: Reciprocating pumps are classified according to the number of cylinders. And also it classified according to the number of piston sides.
8. Simple hand operating pump is also called as ______
a) Froth pump
b) Bicycle pump
c) Multistage pumps
d) Centrifugal pumps
Answer: b
Explanation: Simple hand operating pump is also called as bicycle pumps. It is the simplest pump that is used to inflate bicycle tires and various sporting balls.
9. Internal cavitation in reciprocating pumps occurs due to __________
a) Drag force
b) Cyclic stress
c) Shock waves
d) Flow speed
Answer: c
Explanation: At high pressure, the voids can generate shock waves. Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
10. Bicycle pump generates more compression than volume displacement.
a) True
b) False
Answer: a
Explanation: Bicycle pump generates more compression than volume displacement. Simple hand operating pump is also called as bicycle pumps. It is the simplest pump that is used to inflate bicycle tires and various sporting balls.
11. Power operated pump in which only one side engages the fluid displacement is called _______
a) Froth pump
b) Single acting
c) Double acting
d) Bicycle pump
Answer: b
Explanation: Power operated pump in which only one side engages the fluid displacement is called as single acting reciprocating pump. It consists of piston in only one side of the fluid being displaced.
12. Operation of reciprocating motion is done by a ________ source
a) Power
b) Energy
c) Momentum
d) Inertia
Answer: a
Explanation: Operation of reciprocating motion is done by a power source. This power source consists of electric motor or IC engines. Power source gives rotary motion to crank.
13. An up and down back and forth relative linear motion is called __________
a) Reciprocation
b) Rotation
c) Filtration
d) Excavation
Answer: a
Explanation: An up and down back and forth relative linear motion is called reciprocation. This is how the piston in a reciprocating pump moves.
14. Power operated pump in which only both sides engage the fluid displacement is called _____
a) Froth pump
b) Single acting
c) Double acting
d) Bicycle pump
Answer: c
Explanation: Power operated pump in which both the side engages the fluid displacement is called as double acting reciprocating pump. It consists of piston in both the side of the fluid being displaced.
15. High pressure reciprocating pumps are generally from 1500 HP.
a) True
b) False
Answer: a
Explanation: Yes, it is true. High pressure reciprocating pumps are generally, from 1500 HP. They have a pressure of 20000 PSI and flow rates up to 1000 GPM.
This set of Hydraulic Machines Questions and Answers for Entrance exams focuses on “Main Parts and Working “.
1. How many number of valves are required for the rotary pump?
a) 0
b) 1
c) 2
d) 3
Answer: a
Explanation: There are no valves required for a rotary pump. A rotary pump is the one in which the flow is continuous. Since, the flow is continuous, we do not require any valves.
2. Reciprocating pump is divided into how many types, based on its cylinders?
a) 0
b) 5
c) 2
d) 3
Answer: b
Explanation: Based on the number of cylinders, the reciprocating pump is divided into five types. It is divided on the basis of cylinders as single, double, triple , duplex and quintuplex.
3. At each stage the fluid is directed ________
a) Towards the centre
b) Away the centre
c) Towards the surface
d) Away from the centre
Answer: a
Explanation: At each stage in the centrifugal pump, the fluid is directed to towards the centre. A multistage centrifugal pump has more than two impellers. The multistage centrifugal is similar to the centrifugal pumps working.
4. The maximum efficiency of the reciprocating pump is _________
a) 20
b) 50
c) 70
d) 85
Answer: d
Explanation: Reciprocating pump is more favourable for small liquid quantities. As the chamber in the liquid is trapped, it has a stationary cylinder which contains a piston and a plunger. The maximum efficiency of the reciprocating pump is 85 percent.
5. The two opposite motion that comprise a single reciprocation is called _________
a) Turbocharger
b) Stokes
c) Fluid motion
d) Auto motion
Answer: a
Explanation: Degree of reaction is most commonly used in turbomachinery. Degree of reaction is defined as the ratio of the static pressure drop in the rotor to the static pressure drop in the stage. It can also be defined in the same way for enthalpy in different stages. It is denoted by the letter ‘R’.
6. Reciprocating pumps has ____ efficiency compared to centrifugal pumps
a) Higher
b) Lower
c) Equal
d) Exponential
Answer: b
Explanation: Reciprocating pumps has lower efficiency compared to centrifugal pumps. They are generally just used for discharges at higher heads. Their main purpose is to pump water in hilly areas.
7. Reciprocating pumps works on the principle of __________
a) Drag force
b) Liquid flow push
c) Shock waves
d) Flow speed
Answer: b
Explanation: Reciprocating pumps works on the principle of liquid flow push by a piston that reciprocates in a closed fitting cylinder.
8. Reciprocating pump is a type of ___________
a) Positive displacement pump
b) Bicycle pump
c) Multistage pumps
d) Centrifugal pumps
Answer: a
Explanation: Reciprocating pump is a type of positive displacement pump. The positive displacement pump includes piston pump, diaphragm and plunger pump.
9. During the suction stroke the _______ moves left thus creating vacuum in the Cylinder.
a) Piston
b) Cylinder
c) Valve
d) Pump
Answer: a
Explanation: During the suction stroke the piston moves left. Thus, a vacuum is created in the cylinder. This vacuum causes the suction valve to open and water enters the Cylinder.
10. In reciprocating pumps, the chamber in which the liquid is trapped is a stationary cylinder that contains piston or cylinder
a) True
b) False
Answer: a
Explanation: In reciprocating pumps, the chamber in which the liquid is trapped is a stationary cylinder that contains piston or cylinder.
11. Reciprocating pump works like a positive displacement pump.
a) True
b) False
Answer: a
Explanation: Reciprocating pump works like a positive displacement pump. In reciprocating pumps, the chamber in which the liquid is trapped is a stationary cylinder that contains piston or cylinder.
12. When both the sources are effective it is called as __________
a) Double acting pump
b) Single acting pump
c) Triple acting pump
d) Normal pump
Answer: a
Explanation: When both the sources are effective it is called as double acting centrifugal pump. The pumping unit consists of piston and cylinder.
13. A repetitive variation about the central value of equilibrium is called ________
a) Reciprocation
b) Oscillation
c) Filtration
d) Excavation
Answer: b
Explanation: A repetitive variation about the central value of equilibrium is called as oscillation. It need not be linear.
14. A linear wheel turning motion is called as a ________
a) Reciprocation
b) Rotation
c) Oscillation
d) Bicycle pump
Answer: b
Explanation: A linear wheel turning motion is called as a rotational motion. It is linear motion that takes place along a circular section.
15. A reciprocating pump that has 1200 crank is _________
a) Froth pump
b) Single acting
c) Double acting
d) Triple acting
Answer: d
Explanation: A reciprocating pump that has 1200 crank is triple acting or triple cylinder pump. Each cylinder in a reciprocating pump has it suction and delivery pipes. Thus, has a crank of 1200.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Discharge of Reciprocating Pumps”.
1. In a positive displacement pump, what gets displaced?
a) Fluid
b) Volume
c) Pressure
d) Temperature
Answer: b
Explanation: Reciprocation pump is a type of positive displacement pump. It has a piston pump, plunger and diaphragm. Reciprocating pumps have a good life provided that they are not left untouched. The fluid gets displaced in a positive displacement pump.
2. What happens to the reciprocating pump when left untouched?
a) Efficiency decreases
b) Wear and tear
c) Surface expansion
d) Pressure change
Answer: c
Explanation: When left untouched over a period of time, the reciprocating pump undergoes wear and tear. Reciprocating pumps have a good life provided that they are not left untouched.
3. Positive displacement pumps are capable of developing ______ pressures, in _______ suction pressure.
a) High, low
b) Low, high
c) High, high
d) Low, low
Answer: a
Explanation: Positive displacement pumps are capable of developing high pressures, in low suction pressure. Reciprocation pump is a type of positive displacement pump.
4. When is a reciprocating pump used?
a) When quantity of liquid is small
b) When quantity of liquid is large
c) To pump high pressure
d) To pump low pressure
Answer: a
Explanation: Reciprocating pump is more favourable for small liquid quantities. As the chamber in the liquid is trapped, it has a stationary cylinder which contains a piston and a plunger.
5. Positive displacement pumps are also called as__________
a) Constant pressure pump
b) Pressure drag pumps
c) Constant volume pumps
d) Constant head pumps
Answer: c
Explanation: Positive displacement pumps are also called as constant volume pumps. Positive displacement pumps are capable of developing high pressures, in low suction pressure. Reciprocation pump is a type of positive displacement pump.
6. At high pressure, the voids can generate ______
a) Drag force
b) Mass density
c) Shock waves
d) Flow speed
Answer: c
Explanation: At high pressure, the voids can generate shock waves. Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
7. In centrifugal pumps, their capacity is affected due to___________
a) Drag force
b) Cyclic stress
c) Shock waves
d) Pressure
Answer: d
Explanation: In centrifugal pumps, their capacity is affected due to the presence of pressure that works against the pump they operate.
8. A quantity of fluid that leaks from a higher pressure discharge to a lower pressure discharge is called______
a) Slip
b) Heat
c) Friction
d) Enthalpy
Answer: a
Explanation: Slip is defined as the quantity of fluid that leaks from a higher pressure discharge to a lower pressure discharge.
9. Positive displacement pumps regulate the flow by varying its ________
a) Drag force
b) Cyclic stress
c) Shock waves
d) Flow speed
Answer: d
Explanation: Positive displacement pumps regulate the flow by varying its flow speed. This happens by the pump or by the process of recycling. Positive displacement pumps are also called as constant volume pumps.
10. Positive displacement pumps are divided into two types.
a) True
b) False
Answer: a
Explanation: Yes, Positive displacement pumps are divided into two types. The two types are reciprocating pumps and rotary pumps. Both these pumps differ in their working and construction.
11. Centrifugal pump is less efficient than a reciprocating pump because of its _______
a) Temperature
b) Speed
c) Heat
d) Cost
Answer: d
Explanation: Centrifugal pump is less efficient than a reciprocating pump because of its cost of maintenance. Cost factor plays an important role in determining the efficiency.
12. Simplest example of single acting reciprocating pump is _______
a) Mineral ores
b) Whirl wheels
c) Bicycle tires
d) Syringe
Answer: d
Explanation: Simplest example of single acting reciprocating pump is a syringe. Power operated pump in which only one side engages the fluid displacement is called as single acting reciprocating pump. It consists of piston in only one side of the fluid being displaced.
13. Rotary pumps do not function well under _______
a) High Vaporisation
b) High Sedimentation
c) High viscosity
d) Excavation
Answer: c
Explanation: Rotary pumps do not function well under high viscosity fluid. Theses pumps are normally limited to services during the increase of such parameters.
14. The parameter that disturbs the working of the rotary pump is______
a) High Vaporisation
b) High Sedimentation
c) Low flow rate
d) Excavation
Answer: c
Explanation: The parameter that disturbs the working of the rotary pump is low flow rate and a high viscosity. Theses pumps are normally limited to services during the increase of such parameters.
15. In a double acting reciprocating pump, the piston carries suction and expulsion at the same time.
a) True
b) False
Answer: a
Explanation: Yes, it is true. In a double acting reciprocating pump, the piston carries suction and expulsion at the same time. It consists of piston in both the side of the fluid being displaced.
This set of Hydraulic Machines online test focuses on “Work done by Reciprocating Pumps”.
1. Rotary pumps are commonly used to circulate________
a) Lube oils
b) Petroleum
c) Diesel
d) Water
Answer: a
Explanation: There are no valves required for a rotary pump. A rotary pump is the one in which the flow is continuous. Since, the flow is continuous, it circulates lube oils in different turbomachinery.
2. Reciprocating pump is divided into how many types, based on its cylinders?
a) 0
b) 5
c) 2
d) 3
Answer: b
Explanation: Based on the number of cylinders, the reciprocating pump is divided into five types. It is divided on the basis of cylinders as single, double, triple , duplex and quintuplex.
3. How many number of valves are required for the rotary pump?
a) 0
b) 1
c) 2
d) 3
Answer: a
Explanation: There are no valves required for a rotary pump. A rotary pump is the one in which the flow is continuous. Since, the flow is continuous, we do not require any valves.
4. Capacity of a rotary pump is defined as _________
a) Total liquid displaced
b) Overall performance of pump
c) Maximum fluid flow
d) Minimum fluid flow
Answer: a
Explanation: Capacity of a rotary pump is defined as the total displacement of the pump with lesser amount of slip. Thus, the correct option for the capacity of pump is ‘a’.
5. The pump that converts mechanical energy into hydraulic energy is called as _________
a) Turbomachinery
b) Centrifugal pump
c) Aerodynamics
d) Auto pump
Answer: b
Explanation: The pump that converts mechanical energy into hydraulic energy is called as centrifugal pump.
6. What type of flow does the reciprocating pump have?
a) Uniform
b) Continuous
c) Pulsating
d) Non-uniform
Answer: b
Explanation: The reciprocating pump has a continuous flow because of its constant discharge even with the variations in the delivery side.
7. What is the full form of PD?
a) Positive displacement
b) Pump displacement
c) Plunger displacement
d) Plunger direct
Answer: a
Explanation: PD stands for positive displacement pump. Reciprocating pump is a positive displacement.
8. Why can’t rotary pumps non-lubricate water?
a) Because it has lesser viscosity
b) Because it contains abrasive particles
c) Multistage pumps are difficult to operate
d) Draft tube is thin
Answer: b
Explanation: A rotary pump cannot non lubricate fluids such as water because water contains hard abrasive particles or hard substances.
9. The maximum speed of reciprocating pump is __________
a) 20m/min
b) 30m/min
c) 40m/min
d) 50m/min
Answer: b
Explanation: The maximum speed of reciprocating pump is only 30m/min. Reciprocating pump runs at a very low speed. When they are connected to driving machines, speed reducing device is required.
10. Pumps require clearances because of machining tolerances or wear exhibits larger slip.
a) True
b) False
Answer: a
Explanation: Pumps require clearances because of machining tolerances or wear exhibits larger slip. Reciprocating pump runs at a very low speed. When they are connected to driving machines, speed reducing device is required.
11. The pump that uses a relatively smaller amount of liquid is called ________
a) Froth pump
b) Reciprocating pump
c) Double acting
d) Bicycle pump
Answer: b
Explanation: The pump that uses a relatively smaller amount of liquid is called as reciprocating pump. It is a positive displacement pump.
12. Sliding vanes in pumps are held by ________
a) Draft pins
b) Whirl wheels
c) Springs
d) Nails
Answer: c
Explanation: Sliding vanes is mounted on a rotor in which the vanes slide in and out of the rotor. These sliding vanes are held by springs or sealer rings.
13. Air vessel accumulates excess quantity of ______
a) Vapor
b) Water
c) Heat
d) Pressure
Answer: b
Explanation: Air vessel accumulates excess quantity of water flowing in the suction pipe or delivery pipe.
14. In which pump is the liquid in contact with both the sides of the plunger_____
a) Froth pump
b) Single acting
c) Double acting
d) Bicycle pump
Answer: c
Explanation: Power operated pump in which both the side engages the fluid displacement is called as double acting reciprocating pump. It consists of piston in both the side of the fluid being displaced.
15. The sliding vane is capable of delivering medium capacity and heat.
a) True
b) False
Answer: a
Explanation: The sliding vane is capable of delivering medium capacity and heat. Sliding vanes is mounted on a rotor in which the vanes slide in and out of the rotor. These sliding vanes are held by springs or sealer rings.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Double Acting Pumps”.
1. When a cylinder has inlet and outlet ports at each end, then it is called as __________
a) Double acting
b) Air lift pumps
c) Reciprocating pumps
d) Centrifugal pumps
Answer: a
Explanation: When a cylinder has inlet and outlet ports at each end, then it is called as double acting pumps. It operates similar to the single acting pump with respect to its motion.
2. Turbomachines work under ________
a) Newtons first law
b) Newtons second law
c) Newtons third law
d) Kepler’s law
Answer: b
Explanation: Turbomachines work under Newtons second law. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
3. The main function of nozzle is to __________
a) Varying temperatures
b) Pressure variations
c) Load variations
d) Heat variations
Answer: b
Explanation: The main function of nozzle is to vary the pressure of fluid passing through the nozzle. It is done by opening and shutting the sets of nozzles. Thus, its main function is to regulate pressure of the fluid.
4. When the piston moves forward, liquid is drawn ________
a) Into the cylinder
b) Away from the cylinder
c) Into the draft tube
d) Away from the draft tube
Answer: a
Explanation: When the piston moves forward, liquid is drawn into the cylinder head. When a cylinder has inlet and outlet ports at each end, then it is called as double acting pumps. It operates similar to the single acting pump with respect to its motion.
5. The pump injects compressed air at the _________
a) Rotor pipe
b) Bottom of the discharge pipe
c) Top of the discharge pipe
d) Rotor to draft
Answer: b
Explanation: An airlift pump injects the compressed air at the bottom of the discharge pipe. A pump that has low suction and moderate discharge is called air lift pumps. These pumps have a moderate discharge with liquid and entrained solids.
6. In a reciprocating pump, with the change in discharge pressure, ________
a) The Volume delivered increases
b) The volume delivered decreases
c) Volume delivered remains the same
d) Volume delivered is independent
Answer: c
Explanation: Irrespective of the change in the discharge pressure, the volume of the fluid delivered remains the same in a reciprocating pump. Thus, it does even vary with the slight increase or decrease of the pump.
7. The compressed air mixes with the liquid casing to become less dense.
a) True
b) False
Answer: a
Explanation: The compressed air mixes with the liquid casing to become less denser that the rest of the liquid. This is because it will get displaced upwards through the discharge pipe.
8. The amount of fluid that leaks internally is called ________
a) Head race
b) Slip
c) Tail race
d) Internal friction
Answer: b
Explanation: The amount of fluid that leaks internally is called as slip. The slip indicates the condition of the pump to improve its overall efficiency.
9. Airlift pumps are widely used in aquaculture to pump.
a) True
b) False
Answer: a
Explanation: The statement is true. Airlift pumps are widely used in aquaculture to pump. It also circulates and aerates the water in a closed environment. This helps it to recirculate in system and ponds.
10. Centrifugal pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid
Answer: d
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.
11. For a good condition, slip should be________
a) Below 1 percent
b) 1 to 2 percent
c) 3 to 4 percent
d) Above 5 percent
Answer: a
Explanation: For a good condition of the pump, the slip should be below 1 percent. The amount of fluid that leaks internally is called as slip. The slip indicates the condition of the pump to improve its overall efficiency.
12. If the slip is above 5 percent, the pumps needs to be ______
a) Dragged
b) Overhauled
c) Retracted
d) Intermittent
Answer: b
Explanation: If the slip is above 5 percent, the pumps needs to be overhauled. The amount of fluid that leaks internally is called as slip. The slip indicates the condition of the pump to improve its overall efficiency.
13. The rotational kinetic energy comes from ______
a) Engine motor
b) Pump
c) Tank
d) Draft tube
Answer: a
Explanation: Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. The rotational kinetic energy comes from engine or electrical motor.
14. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. Slip in a pump depends on which of following parameters?
a) Wear
b) Pressure
c) Temperature
d) Heat
Answer: a
Explanation: The slip on the pump remains a constant most of the time. The slip changes only when the wear is not rapid. The amount of fluid that leaks internally is called as slip. The slip indicates the condition of the pump to improve its overall efficiency.
This set of Hydraulic Machines Question Bank focuses on “Slip of Reciprocating Pump”.
1. Internal breakage in a pump mainly takes place when ________
a) Discharge pressure is increased
b) Temperature is increased
c) Heat leads to expansion
d) Corrosion takes place
Answer: a
Explanation: Internal breakage in a pump mainly takes place when the discharge pressure in the pump is increased in between that of the piston rings and the cylinder liner or the leading internal valves.
2. During internal breakage, output power ________
a) Increases
b) Decreases
c) Remains same
d) Independent
Answer: b
Explanation: During internal breakage, output power decreases. This is an important measure to determine the volumetric efficiency of the pump.
3. The output that we get after an internal breakage can be classed as _________
a) An increase
b) A decrease
c) Constant
d) An independent variable
Answer: c
Explanation: The output that we get after an internal breakage can be classed as an independent variable. During internal breakage, output power decreases. This is an important measure to determine the volumetric efficiency of the pump.
4. When the hydraulic fluid forms on only one side of the piston, it is called _______
a) Single acting pump
b) Double acting pump
c) Froth pump
d) Draft tube
Answer: a
Explanation: When the hydraulic fluid forms on only one side of the piston, it is called a single acting pump.
5. The speed of the reciprocating pump is generally measured in ______
a) Stokes.min
b) Stokes/min
c) rps
d) rp/s
Answer: b
Explanation: The speed of the reciprocating pump is generally measured in stokes/min. This is the number of times the piston moves backward and forth in one minute. It can also be measured in rpm.
6. A pump with two steams and two water cylinders is called ________
a) Single acting pump
b) Double acting pump
c) Froth pump
d) Duplex pump
Answer: d
Explanation: A pump with two steams and two water cylinders is called duplex pumps. It consists of a basic hydraulic system layout.
7. Reciprocating pumps can deliver fluid at high pressure.
a) True
b) False
Answer: a
Explanation: Reciprocating pumps can deliver fluid at high pressure. It can do it with its high delivery head. This is one of the major advantage of reciprocating pumps.
8. When an external force is not available in a pump, we use a ________
a) Hydraulic cylinder
b) Slip gauge
c) Tail race
d) Heater
Answer: a
Explanation: When an external force is not available in a pump, we use a hydraulic cylinder attached at the port end.
9. Piston pumps are self priming.
a) True
b) False
Answer: a
Explanation: The statement is true. Piston pumps are self priming. They do not need cylinders to be filled before the starting of the operation. This is one of the major advantage of the piston pumps.
10. Reciprocating pumps give a ________ flow
a) Uniform
b) Non- uniform
c) Pulsating
d) Sinusoidal
Answer: c
Explanation: Reciprocating pumps give a pulsating flow. Reciprocating pumps can deliver fluid at high pressure. It can do it with its high delivery head. This is one of the major advantage of reciprocating pumps.
11. Suction stroke becomes difficult to pump ______
a) High temperature fluids
b) Viscous fluids
c) Fluids with abrasives
d) High velocity fluids
Answer: b
Explanation: For a good condition of the pump, the slip should be below 1 percent. Suction stroke becomes difficult to pump when the fluid is of high viscosity.
12. Piston pumps are very _______
a) Expensive
b) Cheap
c) Reasonable
d) Intricate
Answer: a
Explanation: The piston pumps are very expensive because of their accurate sizes of the cylinders and their pistons. Also, they require a conversion of their gearing that involves extra equipment cost.
13. What is the full form of DAC?
a) Digital Acting pumps
b) Double acting pumps
c) Data acting pumps
d) Draft tube pumps
Answer: b
Explanation: DAC stands for Double acting pumps. Suction stroke becomes difficult to pump when the fluid is of high viscosity in a double acting pump.
14. Which among the following is not a multi-cylinder pump?
a) Double acting simplex
b) Single acting duplex
c) Double acting duplex
d) Single acting triplex
Answer: a
Explanation: Double acting simplex is not a multi-cylinder pump. It is a single cylinder pump. The more the double acting cylinders in a pump, the smoother the operation is providing a better output.
15. As the motor rotates the flywheel, the eccentrically mounted connecting rod rotates with it.
a) True
b) False
Answer: a
Explanation: As the motor rotates the flywheel, the eccentrically mounted connecting rod rotates with it. The other end of the connecting rod is coupled to the slide assembly or the cross head gear.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Air Vessels”.
1. A pressure vessel is used to hold _______
a) Air
b) Gases
c) Molecules
d) Solids
Answer: b
Explanation: The pressure vessels in most turbomachinery are used to hold liquid and gasses at a pressure that is different from an ambient pressure.
2. Why do we need a maximum safe operating pressure?
a) Pressure vessel might explode
b) Temperature increase needs to be controlled
c) Heat transfer is rejected
d) Improve overall efficiency
Answer: a
Explanation: Pressure vessels need to be operated under low conditions as they might explode due to increase in pressure. The pressure vessels in most turbomachinery are used to hold liquid and gasses at a pressure that is different from an ambient pressure.
3. When is a reciprocating pump used?
a) When quantity of liquid is small
b) When quantity of liquid is large
c) To pump high pressure
d) To pump low pressure
Answer: a
Explanation: Reciprocating pump is used when the quantity of liquid is small. Because handling such small quantity liquids is difficult. Especially when the delivery pressure is quite large.
4. The maximum efficiency of the reciprocating pump is _________
a) 20
b) 50
c) 70
d) 85
Answer: d
Explanation: Reciprocating pump is more favourable for small liquid quantities. As the chamber in the liquid is trapped, it has a stationary cylinder which contains a piston and a plunger. The maximum efficiency of the reciprocating pump is 85 percent.
5. A tank that is used to protect closed water heating systems is called ________
a) Pressure vessel
b) Expansion vessel
c) Heat vessel
d) Auto vessel
Answer: b
Explanation: A tank that is used to protect closed water heating systems is called expansion vessel. It is essential for heating process of water.
6. How is the construction of the vessel tested?
a) Uniform testing
b) Continuous testing
c) Pulsating test
d) Non-destructive testing
Answer: d
Explanation: Pressure vessels are tested using non-destructive testing also called the NDT. It is a very essential method to determine the defects in the turbomachinery.
7. What does BPVC stand for?
a) Boiler and pressure vessel code
b) Boiler and pump vessel code
c) Boiler and pressure vessel clutch
d) Boiler and pump vessel clutch
Answer: a
Explanation: BPVC stands for Boiler and pressure vessel code. It is a standard code for determining the pressure that the pressure vessels can withstand.
8. Which of the following is not an NDT type?
a) Ultrasonic
b) Liquid penetrant
c) Visual
d) Hammer test
Answer: d
Explanation: Hammer test is not a non destructive type of testing. Some of the examples of destructive testing are ultrasonic, radiography, liquid penetrant and visual testing.
9. What is the full form of NDI?
a) Non-destructive intern
b) Non-destructive inspection
c) Non-destructive inkling
d) Non-destructive inertia
Answer: b
Explanation: The full form of NDI is Non-destructive inspection. It is a very essential method to determine the defects in the turbomachinery.
10. NDT is a money and time saving technique.
a) True
b) False
Answer: a
Explanation: NDT is a money and time saving technique because it does not permanently alter the article that is being inspected. It does evaluation, trouble shooting and research work.
11. Where is the excess quantity of water from the pump accumulated?
a) Froth tube
b) Draft tube
c) Air vessels
d) Bicycle pump
Answer: c
Explanation: The excess quantity of water is accumulated in air vessels. Air vessels help to maintain high temperature and pressure of fluid.
12. NDT relies upon _________
a) Electromagnetic radiation
b) Heat
c) Pressure change
d) Temperature
Answer: a
Explanation: NDT relies upon sound and electromagnetic radiation. NDT is a money and time saving technique because it does not permanently alter the article that is being inspected. It does evaluation, trouble shooting and research work.
13. What is the shape of a pressure vessel?
a) Square
b) Spheres
c) Cones
d) All the shapes
Answer: d
Explanation: Pressure vessel can be made of any shape. It is most commonly made up in spheres, cones , cylinders and cut into different sections with different cross sections.
14. Safety valve is used to ensure that the pressure in the vessels is not exceeded.
a) True
b) False
Answer: a
Explanation: Safety valve is used to ensure that the pressure in the vessels is not exceeded. Safety valve is also called as the relief valve. It has an intricate design to serve this purpose.
15. Pressure vessel closures are used to _________
a) Avoid breakage
b) Avoid leakage
c) Retain structures
d) Maintain pressure
Answer: c
Explanation: Pressure vessel closures are used for retaining structures. It is designed in such a way to provide quick access to pressure vessels, pipelines and filtration systems.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Hydraulic Press and Accumulator”.
1. The hydraulic press is also known as _________ press.
a) Pascal
b) Toricelli
c) Bernouille
d) Bramah
Answer: d
Explanation: The hydraulic press is also known as Bramah’s press. It was invented by Joseph Bramah, from England. Hence, it was named after him.
2. The underlying principle behind a hydraulic press is based on ______ principle.
a) Bramah’s
b) Pascal’s
c) Stoke’s
d) Newton’s
Answer: b
Explanation: The underlying principle behind a hydraulic press is Pascal’s principle. It states that the pressure throughout a closed system is constant. This pressure is applied with an equal force on equal areas and at right angles to the container wall.
3. In a hydraulic press, the pump acts as a _________
a) Piston
b) Motor
c) Tubing
d) Cylinder
Answer: a
Explanation: In a hydraulic press, the pump acts as a piston. It will have a considerable mechanical force acting on a small cross-sectional area. The other part is a piston is large area which will deliver a higher mechanical force.
4. A hydraulic press makes use of a _________
a) hydraulic pump
b) hydraulic cylinder
c) hydraulic accumulator
d) hydraulic shaft
Answer: b
Explanation: A hydraulic press utilizes a hydraulic cylinder. This cylinder is used to generate a compressive force. It’s working is similar to that of a hydraulic lever.
5. In a hydraulic press, the metal can be _______
a) Crushed
b) Straightened
c) Molded
d) Crushes, straightened and molded
Answer: d
Explanation: The metallic material placed in a hydraulic press can be crushed, straightened and molded. These are some of the crucial features of a hydraulic press. It consists of a bed or plate on which this metal is placed for the action to take place.
6. The cylinder with the smaller diameter Is called _________
a) Slave cylinder
b) Master cylinder
c) Working cylinder
d) Casting Cylinder
Answer: a
Explanation: The cylinder with the smaller diameter is called the slave cylinder. The hydraulic press consists of 2 cylinders. These are classified as master and slave cylinder depending on their diameters.
7. A ________ is the main essence of a car crushing system.
a) hydraulic press
b) hydraulic cylinder
c) hydraulic crane
d) accumulator
Answer: a
Explanation: The main essence of a car crushing system is a hydraulic press. In this process, a hydraulic motor applies a large pressure on the fluids into the cylinders. The fluid pressure makes the plates rise and with a large force, the plate is driven on the car thereby crushing it.
8. The cylinder having the larger diameter is called _______ cylinder.
a) Slave
b) Master
c) Cage
d) Pump
Answer: b
Explanation: The cylinder with the larger diameter is called the master cylinder. The hydraulic press consists of 2 cylinders. These are classified as master and slave cylinder depending on their diameters.
9. A ________ is a storage reservoir under pressure where a liquid is held under pressure.
a) Hydraulic accumulator
b) Hydraulic crane
c) Hydraulic gear
d) Hydraulic pump
Answer: a
Explanation: A hydraulic accumulator is a storage reservoir under pressure where a liquid is stored under pressure. The fluid is mostly a non-compressible hydraulic fluid. This pressure is usually applied by an external source.
10. The most frequently used accumulator type is ________
a) Liquid accumulator
b) Solid accumulator
c) Compressed gas accumulator
d) Plasma accumulator
Answer: c
Explanation: The most common accumulator type is compressed gas accumulator. It Is also known as hydro-pneumatic accumulator. They have a wide range of application.
11. The first accumulators for Armstrong’s hydraulic dock machinery were ________ which is placed raised.
a) oil towers
b) gas towers
c) water towers
d) plasma towers
Answer: c
Explanation: The first accumulators for Armstrong’s hydraulic dock machinery were raised water towers Water was pumped to a tank at the top of these towers by steam pumps. When dock machinery required hydraulic power, the hydrostatic head of the water’s height above ground provided the necessary pressure.
12. ________ is the simplest form of an accumulator.
a) air filled
b) oil filled
c) water filled
d) gas filled
Answer: a
Explanation: Air filled accumulator is one of the simplest accumulators. It is an enclosed space. It is filled with air.
13. ________ invented the compressed air accumulator.
a) Reynold
b) Braman
c) Pascal
d) Jean Mercier
Answer: d
Explanation: The compressed air accumulator was invented by Jean Mercier. It was invented for use in variable pitch propellers. It is the most commonly used accumulator.
14. The inert gas used in gas compressed accumulator is usually _______
a) Sulphur
b) Nitrogen
c) Oxygen
d) Carbon dioxide
Answer: b
Explanation: The inert gas used in a gas compressed accumulator is usually nitrogen. It generates the required compressive force for the liquid. The volume of this gas is inversely proportional to the pressure exerted by this gas.
15. Spring type accumulator works on the principle of ______
a) Bernouille’s law
b) Charles’ law
c) Hooke’s law3
d) Pascal’s law
Answer: c
Explanation: Spring type accumulator works on the principle of Hooke’s law. Hooke’s law states that the magnitude of the force exerted by a spring is linearly proportional to its length change. Hence, as the spring compresses, the force it exerts on the fluid is accelerated linearly.
This set of Hydraulic Machines online quiz focuses on “Hydraulic Intensifier and Hydraulic Ram”.
1. A __________ is a hydraulic machine for converting hydraulic power at low pressure into a reduced volume at higher pressure.
a) Hydraulic Ram
b) Hydraulic crane
c) Hydraulic Intensifier
d) Hydraulic accumulator
Answer: c
Explanation: A hydraulic intensifier is a hydraulic machine for converting hydraulic power at low pressure into a reduced volume at higher pressure. The working volume of the intensifier is limited by the stroke of the piston. This in turn limits the amount of work that may be done by one stroke of the intensifier.
2. If the diameters of the two pistons used in the arrangement are different, the _______ in each cylinder will vary.
a) Hydraulic velocities
b) Hydraulic acceleration
c) Hydraulic pressure
d) Hydraulic force
Answer: c
Explanation: If the diameters of the two pistons used in the arrangement are different, the hydraulic pressure in each cylinder will vary. The hydraulic pressure in both the cylinders will change in the same ratio as their areas. The smaller piston will give rise to a higher pressure.
3. The working volume of the intensifier is restricted by the stroke of the ________
a) Piston
b) Shaft
c) Jack
d) Cylinder
Answer: a
Explanation: The working volume of the intensifier is restricted by the stroke of the piston. As a result of this the amount of work that may be done by one stroke of the intensifier is controlled. These are not reciprocating machines.
4. Intensifiers are employed as a part of machines such as ________
a) Hydraulic presses
b) Hydraulic Crane
c) Hydraulic accumulator
d) Hydraulic Ram
Answer: a
Explanation: Intensifiers are employed as part of machines such as hydraulic presses. Here, a higher pressure is required. Also,a suitable supply is made sure to be already available.
5. Small intensifiers usually have a ________ in their basic system.
a) Stepped piston
b) Stepped cylinder
c) Accumulator
d) Stepped presses
Answer: a
Explanation: Small intensifiers have been constructed with a stepped piston. It is usually a double-ended piston. It consists of two unique diameters where each end works in a different cylinder.
6. Most commonly used hydraulic intensifier for water jet cutting is _________
a) Inline hydraulic intensifier
b) Parallel hydraulic intensifier
c) Pressed hydraulic intensifier
d) Casting hydraulic intensifier
Answer: a
Explanation: Most commonly used hydraulic intensifier for water jet cutting is inline hydraulic intensifier. It is more reliable. Also, it causes the efficiency to be improved.
7. When the intensifier is placed outside its jack, it produces higher ________
a) Pressure
b) Force
c) Displacement
d) Momentum
Answer: a
Explanation: When the intensifier is placed outside its jack, it produces higher pressure. As a result, a smaller cylinder can be used to lift the same force. They are often employed with a powerful hydraulic jack.
8. A ________ is a cyclic water pump that derives its power from hydroelectric sources.
a) Hydraulic crane
b) Hydraulic Ram
c) Hydraulic Accumulator
d) Hydraulic presses
Answer: b
Explanation: A hydraulic ram is a cyclic water pump that derives its power from hydroelectric sources. It is also known as hydram. It takes in water at a particular pressure and flowrate and delivers it at higher pressure and flowrate.
9. A hydraulic ram uses the _______ effect to develop pressure.
a) Water hammer
b) Pascal’s law
c) Bernouille’s
d) Toricelli’s
Answer: a
Explanation: A hydraulic ram uses the water hammer effect to develop pressure. This effect permits a portion of the input water to power a pump. This pump is then lifted to a point higher than where the water originally started.
10. Hydraulic Ram is used in areas where there is a source of ________ power.
a) Thermal
b) Hydroelectric
c) Biogas
d) Solar
Answer: b
Explanation: Hydraulic Ram is used in areas where there is a source of hydroelectric power. There should also be a necessity for pumping water to a destination higher in height than the source. it doesn’t need any any outside source of power than the kinetic energy of flowing water.
11. The typical efficiency of a hydraulic ram is ____
a) 50%
b) 60%
c) 70%
d) 80%
Answer: b
Explanation: The typical efficiency of a hydraulic ram is 60%. This, however , is not the same as volumetric efficiency. Volumetric efficiency relates the volume of water delivered to total water taken from the source.
12. _______ aids in cushioning the shock of the hydraulic pressure during the working of the hydraulic ram
a) Pressure vessel
b) air bags
c) inlet valve
d) Drive pipe
Answer: a
Explanation: Pressure vessel aids in cushioning the shock of the hydraulic pressure during the working of the hydraulic ram. It contains air cushions. It also helps in making the pumping efficiency better.
13. ___________ restricts the dissolution of the pressurized air into the water.
a) Elastic diaphragm
b) Pressure vessel
c) Inlet pipe
d) Waste valve
Answer: a
Explanation: Elastic diaphragm restricts the dissolution of the pressurized air into the water. It is similar in design to an expansion tank. It causes the separation of the air from the water.
14. One of the main reasons why the cycling stops in the hydraulic ram is due to poor adjustment of ________
a) pressure vessel
b) diaphragm
c) waste valve
d) water hammer
Answer: c
Explanation: One of the main reasons why the cycling stops in the hydraulic ram is due to poor adjustment of waste valve. This is a common operational problem. This might cause a lag in the proper delivery of water.
15. An alternate option to the hydraulic ram is _________
a) water-powered pump
b) Oscillating pump
c) Inlet pressure pump
d) Water vessel pump
Answer: a
Explanation: An alternate option to the hydraulic ram is the water-powered pump. It is used when a large flow rate at a high head ratio is needed. A water-powered pump unit is a hydraulic turbine connected to a water pump.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Hydraulic Lift and Hydraulic Crane”.
1. In a hydraulic lift ______ is fixed on the crown of the sliding ram where the carried load is located.
a) Cage
b) Wire rope
c) Pulleys
d) Jiggers
Answer: a
Explanation: Cage is present at the crown of the sliding ram where the carried load is placed. A cage is robust and sturdy. It will provide the required mechanical support for the carried load.
2. When fluid is subjected to _______ it is pushed into the cylindrical chamber which gives the ram gets a push in the upward direction.
a) Pressure
b) Force
c) Momentum
d) Acceleration
Answer: a
Explanation: When high pressure is applied to the fluid, it is pushed into the cylinder. This high pressure is responsible for providing the required thrust to the ram in the upward direction. As a result, the working fluid is always placed under high pressure.
3. ______ is attached to the fixed cylindrical chamber which moves in the upward or downward direction.
a) Jiggers
b) Sliding Ram
c) Crown
d) Pulley
Answer: b
Explanation: Sliding ram Is attached to the fixed cylinder. It enables the cylinder to move in the upward or downward direction. It also has a cage attached to it for mechanical robustness.
4. The two types of pulleys in a hydraulic lift are ______ and ______
a) fixed, fixed
b) movable, fixed
c) movable, movable
d) semi-movable, movable
Answer: b
Explanation: The two types of pulleys available are fixed pulley and movable pulley. The one end of both the pulleys is connected to the sliding ram. The other end of the pulleys is connected to the fixed cylinder.
5. _________ is attached to the wall of the floor, where the sliding ram moves upwards or downwards depending on how the pressure is applied.
a) Cage
b) Fixed cylinder
c) Pulleys
d) shaft
Answer: b
Explanation: The fixed cylinder is attached to the wall of the floor. It is connected to the sliding ram. This cylinder is stationary, whereas the sliding ram can reciprocate depending on how the pressure is applied.
6. Working period is defined as the ratio of the height of lift to the ___________
a) acceleration of the lift
b) pressure of the lift
c) velocity of the lift
d) displacement of the lift.
Answer: c
Explanation: The reciprocal of the ratio of the velocity of the lift to the height of the lift is defined as the working period. This implies that the ratio of the height of the lift to the velocity of the lift is the working period. The greater the working period, the lesser is the velocity of the lift and vice versa.
7. Idle period of lift is defined as the difference of the total time taken for one operation and the _____ of the lift.
a) Working period
b) Stationary period
c) Active period
d) Passive period
Answer: a
Explanation: Idle period of a lift is defined as the difference of the total time taken for a single operation and the working period of the lift. For a constant time, the greater the working period, the lesser is the idle period. The ratio of the height of the lift to the velocity of the lift is the working period.
8. Due to the arrangement of hydraulic jigger, the ________ rotates
a) Fixed cylinder
b) Sliding contact
c) Fluid
d) Pulley
Answer: d
Explanation: Pulley rotates because of the arrangement of the jiggers. The fixed cylinder, as the name suggests, is stationary. The sliding contact is only capable of translatory motion, and not rotatory. The fluid doesn’t rotate. Hence, the answer is narrowed down to pulley.
9. In a hydraulic system the development of pressure is by variable displacement pump and _____
a) stationary pump
b) fixed pump
c) gear pump
d) motor pump
Answer: c
Explanation: The two pumps in a hydraulic crane are variable displacement pump and gear pump. The most commonly used pumps in hydraulic cranes are two gear pumps. They provide the required pressure to pressurize the fluid.
10. In a hydraulic crane __________ is the component mainly responsible for lifting.
a) Boom
b) Counter-weights
c) Jib
d) Rotex Gear
Answer: a
Explanation: Boom is the main component for lifting in hydraulic cranes. It is mechanically robust and strong. It provides the adequate support needed for lifting objects. It is designed so as to withstand heavy weights.
11. ________ helps in indicating the maximum lifting limit of the crane.
a) Jib
b) Gear
c) Shaft
d) Load moment indicator
Answer: d
Explanation: Load moment indicator helps in indicating the maximum lifting limit of the crane. It is a set of lights. These lights start flashing when the maximum limit is reached, thereby indicating a precaution.
12. Out of the ________ a lattice structure called jib projects out.
a) Boom
b) Pump
c) Gear
d) Out-triggers
Answer: a
Explanation: Out of the boom, the jib projects out. It is a lattice structure that provides support to the boom. It is an essential component of the boom.
13. ________ allows the rotation of the boom.
a) Rotex gear
b) Jib
c) Motor
d) Pump
Answer: a
Explanation: Rotex gear allows the rotation of the boom. It is a very large sized gear that is placed under the cab. It provides mobility to the boom.
14. _______ restricts the crane from tipping.
a) Gear
b) Indicator
c) Counterweights3
d) Boom
Answer: c
Explanation: Counterweights restricts the crane from tipping when the lifts take place. They are multi-ton weights. They are usually positioned in the rear side of the cab.
15. The pressure generated by a counterweight gear pump is ______
a) 1200 psi
b) 1300 psi
c) 1400 psi
d) 1500 psi
Answer: c
Explanation: The pressure given out by a counterweight gear pump is 1400 psi. The counterweights are installed to restrict the crane from tipping. A hydraulic lift is used to add or remove them from their place.
This set of Hydraulic Machines Multiple Choice Questions & Answers focuses on “Air Lift Pump and Gear Wheel Pump – 1”.
1. A pump that has low suction and moderate discharge is called _______
a) Froth pumps
b) Air lift pumps
c) Reciprocating pumps
d) Centrifugal pumps
Answer: b
Explanation: A pump that has low suction and moderate discharge is called air lift pumps. These pumps have a moderate discharge with liquid and entrained solids.
2. Turbomachines work under ________
a) Newtons first law
b) Newtons second law
c) Newtons third law
d) Kepler’s law
Answer: b
Explanation: Turbomachines work under Newtons second law. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
3. The main function of nozzle is to __________
a) Varying temperatures
b) Pressure variations
c) Load variations
d) Heat variations
Answer: b
Explanation: The main function of nozzle is to vary the pressure of fluid passing through the nozzle. It is done by opening and shutting the sets of nozzles. Thus, its main function is to regulate pressure of the fluid.
4. The main function of centrifugal pumps are to ________
a) Transfer speed
b) Transfer pressure
c) Transfer temperature
d) Transfer energy
Answer: d
Explanation: The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
5. The pump injects compressed air at the _________
a) Rotor pipe
b) Bottom of the discharge pipe
c) Top of the discharge pipe
d) Rotor to draft
Answer: b
Explanation: An airlift pump injects the compressed air at the bottom of the discharge pipe. A pump that has low suction and moderate discharge is called air lift pumps. These pumps have a moderate discharge with liquid and entrained solids.
6. Which among the following control the flow rate?
a) Valve
b) Pump
c) Head
d) Tank pipe
Answer: a
Explanation: Flow rate of the tank is controlled by the valve. The actuation of individual valve closes. This corresponds to the set of nozzle thereby controlling the actual flow rate of the fluid passing through the valve.
7. The compressed air mixes with the liquid casing to become less dense.
a) True
b) False
Answer: a
Explanation: The compressed air mixes with the liquid casing to become less denser that the rest of the liquid. This is because it will get displaced upwards through the discharge pipe.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
Answer: b
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. Airlift pumps are widely used in aquaculture to pump.
a) True
b) False
Answer: a
Explanation: The statement is true. Airlift pumps are widely used in aquaculture to pump. It also circulates and aerates the water in a closed environment. This helps it to recirculate in system and ponds.
10. Centrifugal pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid
Answer: d
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.
11. The air lift pump works under the principle of _______
a) Newtons equation
b) Buoyancy
c) Momentum conservation
d) Hydrodynamic energy
Answer: b
Explanation: The air lift pump works under the principle of buoyancy force that helps the compressed air to get injected into the lower part of the pipe that transports the liquid.
12. With the increase in load, Energy in the turbine________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. The rotational kinetic energy comes from ______
a) Engine motor
b) Pump
c) Tank
d) Draft tube
Answer: a
Explanation: Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. The rotational kinetic energy comes from engine or electrical motor.
14. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. The fluid coming into the airlift pump is accelerated by ________
a) Throttle
b) Impeller
c) Nozzle
d) Governor
Answer: b
Explanation: The fluid coming into the airlift pump is accelerated by an impeller. The fluid enters the pump along a radially outward direction into the diffuser or a volute chamber.
This set of Hydraulic Machines Interview Questions and Answers for Experienced people focuses on “Air Lift Pump and Gear Wheel Pump – 2”.
1. A gear pump uses ___________
a) Petrochemical pumps
b) Meshing of gears
c) Froth pumps
d) Airlift pumps
Answer: b
Explanation: A gear pump uses meshing of gears. This meshing is done to pump fluid by displacement. Gear pumps are widely used in chemical installations.
2. A pump that has low suction and moderate discharge of liquid is called ________
a) Airlift Pump
b) Vacuum pump
c) Turbine pump
d) Draft tube
Answer: a
Explanation: A pump that has low suction and moderate discharge of liquid is called airlift pump. It plays an essential role in pumping high pressure fluids.
3. The most common pump used for hydraulic fluid power application is __________
a) Centrifugal pumps
b) Gear pump
c) Froth pumps
d) Airlift pumps
Answer: b
Explanation: The most common pump used for hydraulic fluid power application is gear pump. A gear pump uses meshing of gears. This meshing is done to pump fluid by displacement. Gear pumps are widely used in chemical installations.
4. The main function of gear pumps are to ________
a) Transfer speed
b) Transfer pressure
c) Transfer temperature
d) Transfer energy
Answer: d
Explanation: The primary objective of a gear pump is to transfer energy. Gear pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors. It is a mechanical device.
5. Centrifugal pumps transfer energy from _______
a) Rotor to fluid
b) Fluid to rotor
c) Draft to rotor
d) Rotor to draft
Answer: a
Explanation: Centrifugal pumps transfer energy from rotor to fluid. The primary objective of a centrifugal pump is to transfer energy. Centrifugal pump is a turbomachinery.
6. Gear pumps are mainly used in chemical installations because they pump ________
a) High viscosity fluids
b) High density fluids
c) High pressure fluids
d) High temperature fluids
Answer: a
Explanation: Gear pumps are mainly used in chemical installations because they pump high viscosity fluids. They use two external spur gears for this purpose.
7. Gear pumps convert rotational kinetic energy to hydrodynamic energy.
a) True
b) False
Answer: a
Explanation: Gear pumps are used to transport fluids. They transport fluids by conversion of energies. Gear pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy.
8. The injection pumps used in most diesel engines can create up to ________
a) 300 psi
b) 3000 psi
c) 30000 psi
d) 3 psi
Answer: c
Explanation: The injection pumps used in most diesel engines can create up to 30000 psi. It needs to maintain at this pressure in order to operate the fuel injectors.
9. A pneumatic sewage ejector includes a tank for holding _________
a) Fluid sewage
b) Horizontally sewage
c) Axial sewage
d) Radial sewage
Answer: a
Explanation: A pneumatic sewage ejector includes a tank for holding fluid sewage.
10. Gear pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid
Answer: d
Explanation: Gear pumps are used to transport fluids. They transport fluids by conversion of energies. A gear pump uses meshing of gears. This meshing is done to pump fluid by displacement. Gear pumps are widely used in chemical installations.
11. Centrifugal pumps transport fluids by converting _________
a) Kinetic energy to hydrodynamic energy
b) Hydrodynamic energy to kinetic energy
c) Mechanical energy to kinetic energy
d) Mechanical energy to Hydrodynamic energy
Answer: a
Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy.
12. With the increase in load, Energy in the turbine ________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Explanation: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. The rotational kinetic energy comes from ______
a) Engine motor
b) Pump
c) Tank
d) Draft tube
Answer: a
Explanation: Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. The rotational kinetic energy comes from engine or electrical motor.
14. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Explanation: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. Gear pumps are ___________
a) Tangential flow pumps
b) Positive displacement pumps
c) Negative displacement pumps
d) Radial pumps
Answer: a
Explanation: Gear pumps are positive displacement pumps or fixed displacement pumps. This means that they pump at a constant amount of fluid each revolution.
