WorksheetsHydraulic Turbines Quiz 4B
Total questions: 120
Worksheet time: 2hrs 0mins
1. The discharge through a reaction radial flow turbine is given by____________ P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=thickness and Vf=flow velocity
P1*b1*Vf1
P2*b2*Vf2
P1*b2*Vf2
Both P1*b1*Vf1 & P2*b2*Vf2
2. In Inward radial flow reaction turbine if thickness is considered then discharge is _________ 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
(P1-n*t)*b1*Vf1
(P2-n*t)*b2*Vf2
(P1-n*t)*b2*Vf2
Both (P1-n*t)*b1*Vf1 & (P2-n*t)*b2*Vf2
3. 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 _____________
Radial inlet discharge
Radial outlet discharge
Flow ratio
Speed ratio
4. In which of following turbine whirl component is zero?
Reaction turbine
Inward radial flow reaction turbine
Axial flow turbine
Impulse turbine
5. Discharge in inward flow reaction turbine ____________ as the flow takes place in the casing.
Increases
Decreases
Remains constant
Gradually decreases
6. The formation of vapour cavities is called _____
Static pressure drop
Cavitation
Isentropic expansion
Emulsion
7. Cavitation usually occurs due to the changes in ________
Pressure
Temperature
Volume
Heat
8. Which of these ratios are termed to be hydraulic efficiency?
Water power to delivered power
Delivered power to input power
Power lost to power delivered
Runner power to water power
9. Discharge through a reaction turbine is given by, Q = ______
Pi*d*b*Vf1
Pi*d*d*b*Vf1
Pi*d*b*b*Vf2
Pi*b*b*Vf1
10. When the thicknesses of vanes are to be considered in the discharge of a turbine, what will be the area under consideration?
Pi*d – n*t
Pi*d – n*n*t
Pi*d – t*t
Pi*d *d– n*t
11. The speed ratio is defined as u/(2gH)1/2
True
False
12. Flow ratio is defined as Vf1/(2gH)1/2
False
True
13. _________ means the angle made by absolute velocity with the tangent on the wheel is 90 degrees and the component of whirl velocity is zero.
Axial discharge
Tangential discharge
Turbulent discharge
Radial discharge
14. In an outward flow reaction turbine, water from casing enters guiding wheel.
True
False
15. The water from penstocks enters the _____ which is spiral in shape which the area of cross section of casing goes on decreasing gradually
guide wheel
draft tube
casing
runner
16. If the water flows from inward to outward, the turbine is known as _______
Tangential flow turbine
Turbulent low inward flow
Inward flow turbine
Outward flow turbine
17. ___________ is a circular wheel on which a series of smooth, radial curved vanes are fixed.
Guide wheel
Runner
Casing
Draft tube
18. In outward radial flow reaction turbines, tangential velocity at inlet is less than that of the outlet.
False
True
19. In an outward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as ___________
Speed ratio
Flow ratio
Discharge
Radial discharge
20. In an outward radial flow reaction turbine the ratio of tangential velocity at inlet to the given velocity is ______
Speed ratio
Flow ratio
Discharge
Radial discharge
21. Discharge in an outward flow reaction turbine ____________ as fluid flows across spiral structure in the turbine.
Increases
Decreases
Remains constant
Gradually decreases
22. An outward radial reaction turbine has ______
u < u1
u > u1
u = u1
u1 = u = 0
23. In an outward flow reaction turbine, ________
D > D1
D < D1
D = D1
D = D1 = 0
24. Turbine converts _________
Work to energy
Energy to work
Work to Electricity
Work to pressure
25. Turbine extracts energy from________
Reaction ratio
Pressure ratio
Fluid flow
Volumetric ratio
26. In an Inward flow reaction turbine water enters through ______
Outer periphery
Blades
Inner periphery
Pressure angle
27. Where is the turbine not used in generation of electric power among the following?
Solar power
Windmill
Water wheels
Gas plant
28. In an inward flow reaction turbine, the discharge _______ as the flow takes place along the casing.
Increases
Decreases
Same
Independent
29. In impulse turbines with moving blades, there is no _________ in blades of the turbine.
Pressure change
Same pressure
Volumetric change
Pressure independent
30. In impulse turbines with stationary blades, there is_________ in blades of the turbine.
Pressure change
Same pressure
Volumetric change
Pressure independent
31. The Pelton wheel extracts energy from________
Vane angle
Moving fluid
Increase in temperature
Heat rejection
32. Pelton wheel is a Reaction type water turbine.
True
False
33. The outward radial flow reaction turbine is a turbine in which direction of water flow is ___________
Radial direction
Radially inward
Radially outward
Axial direction
34. The energy available at inlet for an outward flow reaction turbine is ________
Potential
Kinetic energy
Pressure energy
Pressure energy and Kinetic energy
35. 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 _______________
Radial inlet discharge
Radial outlet discharge
Flow ratio
Speed ratio
36. In outward radial flow reaction turbine if thickness is considered then discharge is ________
(P1-n*t)*b1*Vf1
(P2-n*t)*b2*Vf2
(P1-n*t)*b2*Vf2
Both (P1-n*t)*b1*Vf1 & (P2-n*t)*b2*Vf2
37. The main difference between reaction turbine and outward radial flow reaction turbine is water flows __________
Radial direction
Radially inward
Radially outward
Axial direction
38. In outward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as ___________
Speed ratio
Flow ratio
Discharge
Radial discharge
39. Conical diffuser draft tube is also called_______
Straight divergent tube
Simple elbow tube
Thermal tube
Elbow tube with varying cross section
40. Conical diffuser draft tube consists of conical diffuser with angles of______
8 degrees
20 degrees
30 degrees
40 degrees
41. What is the purpose of a conical diffuser?
To prevent flow separation
To avoid Pressure drag
To prevent rejection of heat
To increase efficiency
42. What is the water flow direction in a modern Francis turbine?
Axial and then tangential
Tangential and then axial
Radial and then axial
Axial and then radial
43. Which of the following is true in case of flow of water before it enters the runner of a Francis Turbine?
Available head is entirely converted to velocity head
Available head is entire converted to pressure head
Available head is neither converted to pressure head nor velocity head
Available head is partly converted to pressure head and partly to velocity head
44. 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?
To ensure constant velocity of water during runner entry
To prevent loss of efficiency of the turbine due to impulsive forces caused by extra area
To prevent leakage from the turbine
To reduce material costs in order to make the turbine more economical
45. Which of the following profiles are used for guide vanes to ensure smooth flow without separation?
Rectangular
Bent Rectangular
Elliptical
Aerofoil
46. In the velocity diagrams for Francis turbine, which of the following velocity directions is along the blade curvature?
Vr1
Vw1
V1
u1
47. Francis turbine is typically used for which of the following values of available heads?
300 m
100 m
30 m
5 m
48. 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 (kg) flowing across the runner per second.
7500π
50π
300π
RPM of the turbine needs to be given
49. Work done per second by a Francis turbine can be given by ρAVf (Vw1u1 + Vw2u2).
True
False
50. Which of the following terms is considered to be zero while deriving the equation for work done per second for Francis Turbine?
Vr
Vw1
Vf1
Vr1
51. 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:
Is 4 times the original value
Is 2 times the original value
Is ½ times the original value
Is same as the original value
52. 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.
25 kW
1.25 MW
1.25 kW
25 MW
53. 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?
50% increase
25% increase
100% increase
150% increase
54. 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?
0.5 MW
0.25 MW
2 MW
1 MW
55. 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 m3/s. Find the power generated by the turbine?
1700 HP
800 HP
3400 HP
1000 HP
56. 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.
0.33
0.45
0.67
0.89
57. How does the flow ratio (ψ) of a Francis turbine vary with available head (H)?
ψ α H
ψ α 1/H
ψ α sqrt (H)
ψ α 1/(sqrt (H))
58. What is the typical value for flow ratio in a Francis turbine?
0.05 – 0.1
0.15 – 0.30
0.35 – 0.45
0.50 – 0.60
59. 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.
0.56
0.61
0.71
0.81
60. The speed ratio (φ) varies directly with which of the following parameters?
Vw1
V1
N (RPM)
H (Available head)
61. The typical value range of speed ratio for a Francis turbine is:
0.3 – 0.6
0.5 – 0.6
0.1 – 0.4
0.6 – 0.9
62. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
63. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
64. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
65. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
66. 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?
80%
90%
70%
98%
67. 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?
40
60
80
25
68. 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 %)?
60
70
80
90
69. 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 %)?
65
75
80
Mechanical efficiency cannot be found out from the given information
70. 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)?
20
25
22.5
21.5
71. 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?
5
6
10
12
72. 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 %)?
65
75
80
90
73. 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)?
2.85
3.075
6.55
0.285
74. 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)?
80
82.5
83.3
85
75. 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%.
54
5.4
540
0.54
76. 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 %)?
80
85.5
87.5
83.3
77. In a Kaplan turbine, what is the direction of water flow?
Axial and then axial
Radial and then axial
Tangential and then axial
Tangential and then radial
78. For which of the following values of available heads may Kaplan turbine be used?
250 m
100 m
80 m
50 m
79. 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?
Francis turbine
Kaplan Turbine
Propeller Turbine
Pelton turbine
80. 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?
95
75
85
105
81. 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?
V
0.8V
1.2V
2V
82. 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/s2).
0.65
0.72
0.69
0.75
83. 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/s2)?
75.75 m/s
63.25 m/s
23.35 m/s
50.00 m/s
84. 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 (m3/s)?
90
111
125
168
85. In the outlet velocity triangle of a Kaplan turbine, φ = 30o. Vf1 = 5 m/s. What is the relative velocity of the flow at outlet?
10 m/s
5.77 m/s
8.66 m/s
2.88 m/s
86. In the inlet velocity triangle of a Kaplan turbine, α = 45o. The velocity of flow at inlet = 10 m/s. Find the whirl velocity of water at the inlet of Kaplan turbine?
5 m/s
10 m/s
12.5 m/s
15 m/s
87. 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 (In degrees).
53.13
36.86
45
41.41
88. The relative velocity of water at the inlet of the Kaplan turbine is 7 m/s. θ = 75o. The whirl velocity of the water at inlet is 10 m/s. Find the blade velocity of the turbine?
26.124 m/s
40 m/s
36.124 m/s
60 m/s
89. Kaplan turbine works on________
Electrical energy
Hydro energy
Thermal energy
Chemical energy
90. Kaplan turbine belongs to the class of ______ reaction turbine
Inward flow
Outward flow
Radial
Axial
91. The Kaplan Turbine is an evolution of ________
Francis turbine
Pelton wheel
Parsons turbine
Curtis turbine
92. The head of the Kaplan ranges from ______
100 to 200 m
250 to 300 m
10 to 70 m
0 m
93. What type of turbine is Kaplan?
Impulse
Reaction
Energy
Hydro
94. Kaplan turbine is ________ type turbine
Pressure
Inward flow
Outward flow
Velocity
95. 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.
True
False
96. The outlet of the Kaplan turbine is through _______
Vane Blades
Moving pipeline
Draft tube
Pump
97. 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?
80%
90%
70%
98%
98. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
99. 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.
40
60
80
30
100. 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 %)?
60.61
70.71
80.81
90.91
101. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
102. 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?
The numerical value of Q
The available head of the turbine
The RPM or the blade velocity of the turbine
No further information is required
103. 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)?
38
40
42.11
45
104. 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?
4.05
3.15
3.30
2.55
105. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
106. 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 %)?
66.66
75.00
83.33
91.33
107. 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)?
0.831
0.697
1.362
0.298
108. 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)?
57.66
83.63
81.33
79.95
109. 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 %)?
80.05
93.15
87.55
88.35
110. 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?
Hydraulic efficiency
Volumetric efficiency
Mechanical efficiency
Overall efficiency
111. 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%.
78.3
7.83
783
0.783
112. Draft tube is also called_______
Straight divergent tube
Simple elbow tube
Thermal tube
Elbow tube with varying cross section
113. A draft tube helps in converting kinetic energy into________
Electrical work
Mechanical work
Chemical work
Thermal work
114. Draft tube consists of conical diffuser with angles of______
8 deg
20 deg
30 deg
40 deg
115. What is the purpose of a Draft tube?
To prevent flow separation
To avoid Pressure drag
To prevent rejection of heat
To increase efficiency
116. What is the maximum value of efficiency in a draft tube?
100
50
90
40
117. The simple elbow draft tube is placed close to the_______
Head race
Tail race
Tank
Nozzle
118. Turbine that consists of draft tubes is called as__________
Impulse turbine
Curtis turbine
Rateau turbine
Reaction turbine
119. The exit diameter for a simple elbow draft tube should be________
Large
Small
Very small
Same
120. Properties that do not affect a draft tube is _______
Pressure
Temperature
Pressure velocity
Velocity
