Engineering :: Turbo machines
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21. |
The flow on two sides of a normal shock wave is |
A. |
subsonic |
B. |
sonic |
C. |
supersonic |
D. |
supersonic on one side and subsonic on the other side |
Answer: Option D
Explanation:
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22. |
The diverging portion of the nozzle acts as a diffuser for |
A. |
the subsonic flow |
B. |
the supersonic flow |
C. |
both the subsonic as well as supersonic flow |
D. |
none of the above |
Answer: Option A
Explanation:
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23. |
A diffuser |
A. |
converts kinetic energy into thermal energy |
B. |
converts potential energy into kinetic energy |
C. |
converts pressure energy into kinetic energy |
D. |
converts thermal energy into kinetic energy |
Answer: Option A
Explanation:
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24. |
Brayton cycle cannot be used in reciprocating engines even for same compression ratio and work output because |
A. |
Otto cycle is more efficient |
B. |
Brayton cycle is less efficient |
C. |
Brayton cycle is for slow speed engines only |
D. |
Large volume of low pressure gas cannot be efficiently handled in reciprocating engines |
Answer: Option D
Explanation:
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25. |
Actual gas turbine cycle is different from ideal cycle because |
A. |
of internal irreversibility of the process due to friction, turbulence, etc. |
B. |
of variation of specific heats with temperature |
C. |
of losses due to incomplete combustion |
D. |
all of the above |
Answer: Option D
Explanation:
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26. |
The advantage of a gas turbine over a reciprocating engine is |
A. |
perfect balancing of rotor |
B. |
continuous and uniform power |
C. |
usually small working pressures |
D. |
all of the above |
Answer: Option D
Explanation:
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27. |
Overall efficiency of a gas turbine is |
A. |
equal to Rankine cycle efficiency |
B. |
equal to Carnot cycle efficiency |
C. |
less than Diesel cycle efficiency |
D. |
more than Otto or Diesel cycle efficiency |
Answer: Option C
Explanation:
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28. |
Air fuel ratio for a gas turbine is closer to |
Answer: Option D
Explanation:
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29. |
Which of the following is a positive displacement rotory compressor? |
A. |
Roots blower |
B. |
Centrifugal compressor |
C. |
Axial flow compressor |
D. |
All of the above |
Answer: Option A
Explanation:
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30. |
All of the following are positive displacement compressors EXCEPT : |
A. |
Screw compressor |
B. |
Axial flow compressor |
C. |
Roots blower |
D. |
Vane blower |
Answer: Option B
Explanation:
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