Workdone-Francis Turbine MCQs : This section focuses on the "Workdone-Francis Turbine". These Multiple Choice Questions (MCQs) should be practiced to improve the Workdone-Francis Turbine skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
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
Question 2
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
Question 3
How does the flow ratio (Ï) of a Francis turbine vary with available head (H)?
A. Ï Î± H
B. Ï Î± 1/H
C. Ï Î± sqrt (H)
D. Ï Î± 1/(sqrt (H))
Question 4
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
Question 5
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
Question 6
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
Question 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
Question 8
The speed ratio (φ) varies directly with which of the following parameters?
A. Vw1
B. V1
C. N (RPM)
D. H (Available head)
Question 9
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
Question 10
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?
A. 1700 HP
B. 800 HP
C. 3400 HP
D. 1000 HP
Question 11
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
Question 12
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.
A. 7500π
B. 50π
C. 300π
D. RPM of the turbine needs to be given
Question 13
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
Question 14
Work done per second by a Francis turbine can be given by ρAVf (Vw1u1 + Vw2u2).
A. TRUE
B. FALSE
Question 15
How does the flow ratio (ψ) of a Francis turbine vary with available head (H)?
A. ψ α H
B. ψ α 1/H
C. ψ α sqrt (H)
D. ψ α 1/(sqrt (H))