Generic selectors
Exact matches only
Search in title
Search in content
Search in posts
Search in pages
Filter by Categories
nmims post
Objective Type Set
Online MCQ Assignment
Question Solution
Solved Question
Uncategorized

Multiple choice question for engineering

Set 1

1. The formation of vapour cavities is called _____
a) Static pressure drop
b) Cavitation
c) Isentropic expansion
d) Emulsion

View Answer

Answer: b [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: a [Reason:] 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-V22/ V12
b) 1-(V22/ V12)
c) V22/ V12
d) 1- V12

View Answer

Answer: a [Reason:] 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-(V22/ V12).

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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: a [Reason:] 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.

Set 2

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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: b [Reason:] 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/(k*g*q*h), where “k” is known as
a) Density of liquid
b) Specific density of liquid
c) Volume of liquid
d) Specific gravity of liquid

View Answer

Answer: a [Reason:] 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/(k*g*q*h) where k is density of liquid.

8. The expression for maximum hydraulic efficiency of pelton turbine is given by?
a) (1+cos k)/2 where k is outlet blade angle
b) (2+cos k)/2 where k is outlet blade angle
c) (3+cos k)/2 where k is outlet blade angle
d) (4+cos k)/2 where k is outlet blade angle

View Answer

Answer: a [Reason:] 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 (1+cos k)/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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: d [Reason:] 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.

Set 3

1. The efficiency of the draft tube depends on the ______
a) Heat
b) Pressure
c) Temperature
d) Pressure and temperature

View Answer

Answer: d [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: d [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: b [Reason:] 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.

Set 4

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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: d [Reason:] 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%

View Answer

Answer: c [Reason:] 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

View Answer

Answer: a [Reason:] 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 (in %)?
a) 60
b) 70
c) 80
d) 90

View Answer

Answer: c [Reason:] 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 (in %)?
a) 65
b) 75
c) 80
d) Mechanical efficiency cannot be found out from the given information

View Answer

Answer: d [Reason:] 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 m3/s. What is the flow rate of water over the runner blades (in m3/s)?
a) 20
b) 25
c) 22.5
d) 21.5

View Answer

Answer: c [Reason:] 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 m3/s.

10. The volumetric efficiency of a given turbine is 80%. If volume flow rate of water in given to be 30 m3/s, find the volume of water (m3) NOT flowing over the runner blades per second?
a) 5
b) 6
c) 10
d) 12

View Answer

Answer: b [Reason:] The volume of water flowing over runner blades = 0.8*30 = 24 m3/s. The volume of water NOT flowing over the runner blades would then be 30 – 24 = 6 m3/s.

11. The power available at the shaft of a Francis turbine is 1 MW. The volume flow rate of water in 25 m3/s, whirl velocity at inlet is 10 m/s and blade velocity is 5 m/s. Find the mechanical efficiency (in %)?
a) 65
b) 75
c) 80
d) 90

View Answer

Answer: c [Reason:] 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 m3/s. Find the power output available at the shaft if the mechanical efficiency is 95% (in MW)?
a) 2.85
b) 3.075
c) 6.55
d) 0.285

View Answer

Answer: a [Reason:] Mechanical efficiency is given by ηm = shaft power / ρQVw1u1. 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 m3/s at an available head of 60 m. Find the overall efficiency of the turbine in % (g = 10 m/s2)?
a) 80
b) 82.5
c) 83.3
d) 85

View Answer

Answer: c [Reason:] 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 m3/s at an available head of 60 m (g = 10 m/s3). Find the shaft power (in MW) if the overall efficiency of the turbine is 90%.
a) 54
b) 5.4
c) 540
d) 0.54

View Answer

Answer: b [Reason:] 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 (in %)?
a) 80
b) 85.5
c) 87.5
d) 83.3

View Answer

Answer: b [Reason:] Overall efficiency is also given by ηo = ηh*ηm*ηv. So, ηo = 0.90*0.95*1 = 0.855 = 85.5%.

Set 5

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/s2?
a) 80%
b) 90%
c) 70%
d) 98%

View Answer

Answer: b [Reason:] The hydraulic efficiency of a Kaplan turbine is given by ηh = Vw1.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

View Answer

Answer: a [Reason:] 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/s2.
a) 40
b) 60
c) 80
d) 30

View Answer

Answer: d [Reason:] The hydraulic efficiency of a Kaplan 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 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 (in %)?
a) 60.61
b) 70.71
c) 80.81
d) 90.91

View Answer

Answer: d [Reason:] 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

View Answer

Answer: b [Reason:] 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 m3/s. 0.10Q m3/s volume of water do not flow over the runner blades. What further information is required to find the volumetric efficiency (numerical value) 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

View Answer

Answer: d [Reason:] 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 m3/s. What is the flow rate of water over the runner blades (in m3/s)?
a) 38
b) 40
c) 42.11
d) 45

View Answer

Answer: a [Reason:] 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 m3/s, the volume of water over runner blades = 0.95*40 = 38 m3/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 m3/s, find the volume of water (m3) NOT flowing over the runner blades per second?
a) 4.05
b) 3.15
c) 3.30
d) 2.55

View Answer

Answer: b [Reason:] The volume of water flowing over runner blades = 0.91*35 = 31.85 m3/s. The volume of water NOT flowing over the runner blades would then be 35 – 31.85 = 3.15 m3/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

View Answer

Answer: c [Reason:] 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 m3/s, whirl velocity at inlet is 12 m/s and blade velocity is 5 m/s. Find the mechanical efficiency (in %)?
a) 66.66
b) 75.00
c) 83.33
d) 91.33

View Answer

Answer: c [Reason:] Mechanical efficiency of a Kaplan Turbine is given by ηm = 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% (in MW)?
a) 0.831
b) 0.697
c) 1.362
d) 0.298

View Answer

Answer: b [Reason:] 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 m3/s at an available head of 50 m. Find the overall efficiency of the turbine in % (g = 10 m/s2)?
a) 57.66
b) 83.63
c) 81.33
d) 79.95

View Answer

Answer: a [Reason:] 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 (in %)?
a) 80.05
b) 93.15
c) 87.55
d) 88.35

View Answer

Answer: d [Reason:] 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

View Answer

Answer: d [Reason:] 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 m3/s at an available head of 55 m (g = 10 m/s2). Find the shaft power (in MW) if the overall efficiency of the turbine is 95%.
a) 78.3
b) 7.83
c) 783
d) 0.783

View Answer

Answer: b [Reason:] 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.