Discussion
Home ‣ Mechanical Engineering ‣ Steam Nozzles and Turbines Comments
- Question
The efficiency of steam turbines may be improved by
Options- A. reheating of steam
- B. regenerative feed heating
- C. binary vapour plant
- D. any one of these
- Correct Answer
- any one of these
- 1. Parson's reaction turbine is a __________ reaction turbine.
Options- A. 40 percent
- B. 50 percent
- C. 60 percent
- D. 70 percent Discuss
- 2. The blade velocity coefficient is ratio of relative velocity of steam at outlet tip of the blade to the relative velocity of steam at inlet tip of the blade.
Options- A. True
- B. False Discuss
- 3. In reaction turbines, the axial thrust is due to
Options- A. pressure drop across the rotor
- B. change in axial velocity
- C. both (a) and (b)
- D. none of these Discuss
- 4. Which of the following statement is correct?
Options- A. The expansion of steam in a nozzle follows Rankine cycle.
- B. The friction in the nozzle increases the dryness fraction of steam.
- C. The pressure of steam at throat is called critical pressure.
- D. all of the above Discuss
- 5. The steam enters the nozzle at a
Options- A. high pressure and a low velocity
- B. high pressure and a high velocity
- C. low pressure and a low velocity
- D. low pressure and a high velocity Discuss
- 6. The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)
Options- A. V = 44.72 hd K
- B. V = 44.72 K hd
- C. V = 44.72 K hd
- D. V = 44.72 K hd Discuss
- 7. The pressure at which the steam leaves the nozzle is known as back pressure.
Options- A. Correct
- B. Incorrect Discuss
- 8. The difference of supersaturated temperature and saturation temperature at that pressure is called
Options- A. degree of supersaturation
- B. degree of superheat
- C. degree of undercooling
- D. none of these Discuss
- 9. The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be
Options- A. 0.4
- B. 0.56
- C. 0.67
- D. 1.67 Discuss
- 10. The critical pressure gives the velocity of steam at the throat
Options- A. equal to the velocity of sound
- B. less than the velocity of sound
- C. more than the velocity of sound
- D. none of these Discuss
Steam Nozzles and Turbines problems
Search Results
Correct Answer: 50 percent
Correct Answer: True
Correct Answer: both (a) and (b)
Correct Answer: all of the above
Correct Answer: high pressure and a low velocity
Correct Answer: V = 44.72 K hd
Correct Answer: Correct
Correct Answer: degree of undercooling
Correct Answer: 0.4
Correct Answer: equal to the velocity of sound
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