Steam Nozzles and Turbines problems
- 1. During flow through a nozzle, no heat is supplied or rejected by the steam.
Options- A. Agree
- B. Disagree Discuss
Correct Answer: Agree
- 2. 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
Correct Answer: The efficiency of steam turbines is greater than steam engines.
- 3. 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 Discuss
Correct Answer: all of these
- 4. In a nozzle, the effect of supersaturation is to increase the dryness fraction of steam.
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
- 5. 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
Correct Answer: increase the entropy
- 6. 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
Correct Answer: ?1 = ?2 and ?1 = ?2
- 7. When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.
Options- A. increases
- B. decreases Discuss
Correct Answer: decreases
- 8. 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
Correct Answer: Vb = 0.5 V cos ?
- 9. The expansion of steam in a nozzle follows
Options- A. Carnot cycle
- B. Rankine cycle
- C. Joule cycle
- D. Stirling cycle Discuss
Correct Answer: Rankine cycle
- 10. In a 50% reaction turbine stage, tangential component of absolute velocity at rotor inlet is 537 m/s and the blade velocity is 454 m/s. The power output in kW of steam will be
Options- A. 260 kW
- B. 282 kW
- C. 296 kW
- D. 302 kW Discuss
Correct Answer: 282 kW
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