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Home ‣ Mechanical Engineering ‣ Compressors, Gas Dynamics and Gas Turbines Comments
- Question
High air-fuel ratio in gas turbines
Options- A. increases power output
- B. improves thermal efficiency
- C. reduces exhaust temperature
- D. do not damage turbine blades
- Correct Answer
- reduces exhaust temperature
- 1. The total heat rejected in a reciprocating air compressor is equal to the sum of the heat rejected during polytropic compression per kg of air and heat rejected in the intercooler per kg of air.
Options- A. True
- B. False Discuss
- 2. In a centrifugal compressor, an increase in speed at a given pressure ratio causes
Options- A. increase in flow
- B. decrease in flow
- C. increase in efficiency
- D. increase in flow and decrease in efficiency Discuss
- 3. The type of rotary compressor used in aeroplanes, is of
Options- A. centrifugal type
- B. axial flow type
- C. radial flow type
- D. none of these Discuss
- 4. The stagnation pressure rise in a centrifugal compressor takes place
Options- A. in the diffuser only
- B. in the impeller only
- C. in the diffuser and impeller
- D. in the inlet guide vanes only Discuss
- 5. Intercooling in multi-stage compressors is done
Options- A. to cool the air during compression
- B. to cool the air at delivery
- C. to enable compression in two stages
- D. to minimise the work of compression Discuss
- 6. If p1, is the pressure of air entering the L.P. cylinder and p2 is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D1 = Dia. of L.P. cylinder, and D2 = Dia. of H.P. cylinder)
Options- A. D1/D2 = p1p2
- B. D1/D2 = p1/p2
- C. D1/D2 = p2/p1
- D. none of these Discuss
- 7. In a four stage compressor, if the pressure at the first and third stage are 1 bar and 16 bar, then the delivery pressure at the fourth stage will be
Options- A. 1 bar
- B. 16 bar
- C. 64 bar
- D. 256 bar Discuss
- 8. In axial flow compressor, exit flow angle deviation from the blade angle is a function of
Options- A. blade camber
- B. blade camber and incidence angle
- C. space-chord ratio
- D. blade camber and space-chord ratio Discuss
- 9. In a single acting reciprocating compressor, the suction, compression and delivery of air takes place in __________ of the piston.
Options- A. one stroke
- B. two strokes
- C. three strokes
- D. four strokes Discuss
- 10. In a reciprocating air compressor, the compression work per kg of air
Options- A. increases as clearance volume increases
- B. decreases as clearance volume increases
- C. is independent of clearance volume
- D. increases as clearance volume decreases Discuss
Compressors, Gas Dynamics and Gas Turbines problems
Search Results
Correct Answer: True
Correct Answer: increase in flow and decrease in efficiency
Correct Answer: axial flow type
Correct Answer: in the diffuser and impeller
Correct Answer: to minimise the work of compression
Correct Answer: D1/D2 = p2/p1
Correct Answer: 64 bar
Correct Answer: blade camber and incidence angle
Correct Answer: two strokes
Correct Answer: is independent of clearance volume
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