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Home ‣ Mechanical Engineering ‣ Steam Nozzles and Turbines Comments
- Question
Steam turbines may be classified according to
Options- A. direction of steam flow
- B. number of stages
- C. mode of steam action
- D. all of these
- Correct Answer
- all of these
- 1. Which of the following statement is correct?
Options- A. The efficiency of steam turbines is greater than steam engines.
- B. A flywheel is a must for steam turbine.
- C. The turbine blades do not change the direction of steam issuing from the nozzle
- D. The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades Discuss
- 2. During flow through a nozzle, no heat is supplied or rejected by the steam.
Options- A. Agree
- B. Disagree Discuss
- 3. Which of the following statement is wrong?
Options- A. The critical pressure gives the velocity of steam at the throat equal to the velocity of sound.
- B. The flowin the convergent portion of the nozzle is sub-sonic.
- C. The flow in the divergent portion of the nozzle is super-sonic.
- D. To increase the velocity of steam above sonic velocity (super-sonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary. Discuss
- 4. A single stage turbine is not used because it requires large reduction gearing due to very high rotational speed.
Options- A. Agree
- B. Disagree Discuss
- 5. The effect of bleeding is that
Options- A. it increases the thermodynamic efficiency of the turbine
- B. boiler is supplied with hot water
- C. it decreases the power developed by the turbine
- D. all of the above Discuss
- 6. In a nozzle, the effect of supersaturation is to increase the dryness fraction of steam.
Options- A. Yes
- B. No Discuss
- 7. In a nozzle, the effect of supersaturation is to
Options- A. decrease dryness fraction of steam
- B. decrease specific volume of steam
- C. increase the entropy
- D. increase the heat drop Discuss
- 8. For a Parson's reaction turbine, if ?1 and ?2 are fixed blade angles at inlet and exit respectively and ?1 and ?2 are the moving blade angles at entrance and exit respectively, then
Options- A. ?1 = ?2 and ?1 = ?2
- B. ?1 = ?1 and ?2 = ?2
- C. ?1 < ?1 and ?2 > ?2
- D. ?1 = ?2 and ?1 = ?2 Discuss
- 9. When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.
Options- A. increases
- B. decreases Discuss
- 10. The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and ? = Nozzle angle)
Options- A. Vb = 0.5 V cos ?
- B. Vb = V cos ?
- C. Vb = 0.5 V2 cos ?
- D. Vb = V2 cos? Discuss
Steam Nozzles and Turbines problems
Search Results
Correct Answer: The efficiency of steam turbines is greater than steam engines.
Correct Answer: Agree
Correct Answer: To increase the velocity of steam above sonic velocity (super-sonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary.
Correct Answer: Agree
Correct Answer: all of the above
Correct Answer: Yes
Correct Answer: increase the entropy
Correct Answer: ?1 = ?2 and ?1 = ?2
Correct Answer: decreases
Correct Answer: Vb = 0.5 V cos ?
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