Steam Nozzles and Turbines

11. In a single stage impulse turbine, the velocity of steam approaching nozzles is negligible.

A. True
B. False


Correct Answer: A. True

12. Curtis turbine is a

A. simple reaction turbine
B. velocity compounded turbine
C. pressure compounded turbine
D. pressure-velocity compounded turbine


Correct Answer: D. pressure-velocity compounded turbine

13. The velocity of steam at throat of the nozzle is __________ the velocity of sound.

A. equal to
B. less than
C. more than


Correct Answer: A. equal to

14. The critical pressure ratio for initially dry saturated steam is

A. 0.546
B. 0.577
C. 0.582
D. 0.601


Correct Answer: B. 0.577

15. The discharge through a nozzle is maximum for a certain value of exit pressure. This pressure is known as critical pressure.

A. Agree
B. Disagree


Correct Answer: A. Agree

16. The velocity of steam, in reaction turbines, is increased in the fixed blades as well as in moving blades.

A. True
B. False


Correct Answer: A. True

17. The critical pressure ratio for gases is

A. 0.528
B. 0.546
C. 0.577
D. 0.582


Correct Answer: A. 0.528

18. The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.

A. same
B. less
C. more


Correct Answer: B. less

19. The effect of supersaturation is that the

A. mass of the steam discharged increases
B. entropy and specific volume of the steam increases
C. exit velocity of steam reduces
D. all of these


Correct Answer: D. all of these

20. The effect of friction on the flow of steam through a nozzle is to

A. decrease the mass flow rate and to increase the wetness of steam
B. increase the mass flow rate and to increase the exit temperature
C. decrease the mass flow rate and to decrease the wetness of steam
D. increase the exit temperature without any effect on mass flow rate


Correct Answer: C. decrease the mass flow rate and to decrease the wetness of steam

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