Top 550+ Solved Fluid Mechanics and Hydraulic Machines MCQ Questions Answer
Q. Which of the following statements is a definition of the hydraulic efficiency of a turbine?
a. The ratio of power available at the turbine shaft to that supplied to it by runner.
b. The ratio of the power supplied by the runner to the power available at the shaft.
c. The ratio of power utilized by runner to that supplied by the water at entry to the turbine.
d. The ratio of power supplied by water at entry to the power utilized by runner.
Q. The power which appears in the expression for the specific speed is the:
a. Shaft power
b. Water power
c. Power into the turbine
d. None of the above.
Q. Which of the following statements is correct: Runaway speed of a hydraulic turbine is the speed
a. At which there would be no damage to the turbine runner
b. At which the turbine runner can be allowed to run freely without load and with wicket gates wide open
c. Corresponding to maximum overload permissible
d. At full loa
Q. Which of the following statements is correct for a reaction turbine?
a. The outlet must be above the tail race.
b. Water may be allowed to enter a part or whole of wheel circumference.
c. Flow can be regulated without loss.
d. There is only partial conversion of available head to velocity head before entry to rotor.
Q. In a reaction turbine the function of a draft tube is to
a. Provide safety to turbine
b. Prevent air from entering
c. Reconvert the kinetic energy to flow energy
d. Increase the rate of flow
Q. Which of the following statements with respect to a reaction water turbine is incorrect:
a. The spiral casing serves to uniformly distribute water into guide blades
b. The water leaves the turbine at atmospheric pressure
c. The draft tube allows setting of the turbine above the tail race with minimum reduction of available energy
d. The guide vanes direct the flow at proper angle.
Q. Which of the following turbines is suitable for specific speed ranging from 300 to 1000 and heads below 30 m:
a. Francis
b. Kaplan
c. Propeller
d. Pelton.
Q. Specific speed of a turbo-machine
a. Relates the shape rather than the size of the machine
b. Remains unchanged under different condi tions of operation
c. Has the dimensions of rotational speed
d. Is the speed of a machine having unit dimensions.
Q. In an outward radial flow turbine energy conversion process is
a. Purely by reaction only
b. Purely by impulse only
c. Partly by impulse and partly by reaction
d. None of the above.
Q. Which of the following turbines is least efficient under part load conditions:
a. Propeller
b. Kaplan
c. Francis
d. Pelton.
Q. A surge tank is used to
a. Prevent occurrence of hydraulic jump
b. Smoothen the flow
c. Relieve the pipeline of excessive pressure transients
d. Avoid reversal of flow.
Q. Which of the following turbines is most efficient at partload operation?
a. Kaplan
b. Propeller
c. Francis
d. Pelton wheel.
Q. With respect to a Kaplan turbine which of the following statements is incorrect?
a. It employs large guide vane angles than is the case for a Francis turbine.
b. It is designed for flow velocity of mixed flow type.
c. It has blades of small camber to prevent separation.
d. It can adjust both guide vane and blade angles according to rate of discharge.
Q. Specific speed of an impulse turbine (Pelton wheel) ranges from
a. 12 to 70
b. 80 to 400
c. 300 to 1000
d. 1000 to 1200.
Q. Cavitation damage in turbine runner occurs near the
a. Inlet on the convex side of blades
b. Outlet on the convex side of blades
c. Inlet on the concave side of blades
d. Outlet on the concave side of blades.