Steam Nozzles and Turbines problems
- 1. In a reaction turbine
Options- A. the steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades
- B. the expansion of steam takes place partly in the fixed blades and partly in the moving blades
- C. the steam is expanded from a high pressure to a condenser pressure in one or more nozzles
- D. the pressure and temperature of steam remains constant Discuss
Correct Answer: the expansion of steam takes place partly in the fixed blades and partly in the moving blades
- 2. The critical pressure ratio for gases is
Options- A. 0.528
- B. 0.546
- C. 0.577
- D. 0.582 Discuss
Correct Answer: 0.528
- 3. The velocity of steam at throat of the nozzle is __________ the velocity of sound.
Options- A. equal to
- B. less than
- C. more than Discuss
Correct Answer: equal to
- 4. The reheat factor depends upon
Options- A. initial pressure and superheat
- B. exit pressure
- C. turbine stage efficiency
- D. all of these Discuss
Correct Answer: all of these
- 5. The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called
Options- A. blading efficiency
- B. nozzle efficiency
- C. stage efficiency
- D. mechanical efficiency Discuss
Correct Answer: stage efficiency
- 6. The discharge through a nozzle is maximum for a certain value of exit pressure. This pressure is known as critical pressure.
Options- A. Agree
- B. Disagree Discuss
Correct Answer: Agree
- 7. A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be
Options- A. 79 m/s
- B. 188 m/s
- C. 450 m/s
- D. 900 m/s Discuss
Correct Answer: 450 m/s
- 8. In an impulse turbine
Options- A. the steam is expanded in nozzles only and there is a pressure drop and heat drop
- B. the steam is expanded both in fixed and moving blades continuously
- C. the steam is expanded in moving blades only
- D. the pressure and temperature of steam remains constant Discuss
Correct Answer: the steam is expanded in nozzles only and there is a pressure drop and heat drop
- 9. The compounding of turbines is done in order to
Options- A. reduce speed of rotor
- B. improve efficiency
- C. reduce exit losses
- D. all of these Discuss
Correct Answer: all of these
- 10. The efficiency ratio is the ratio of total useful heat drop to the total isentropic heat drop.
Options- A. Agree
- B. Disagree Discuss
Correct Answer: Agree
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