Discussion
Home ‣ Mechanical Engineering ‣ Compressors, Gas Dynamics and Gas Turbines Comments
- Question
Which of the following statement is correct as regard to centrifugal compressors?
Options- A. The flow of air is parallel to the axis of the compressor.
- B. The static pressure of air in the impeller increases in order to provide centripetal force on the air.
- C. The impeller rotates at high speeds.
- D. The maximum efficiency is higher than multi-stage axial flow compressors.
- Correct Answer
- The static pressure of air in the impeller increases in order to provide centripetal force on the air.
- 1. The axial flow compressor is preferred in air-craft gas turbines because of
Options- A. low frontal area
- B. higher thrust
- C. high pressure rise
- D. none of these Discuss
- 2. The process, which causes the air to enter the impeller blades of a centrifugal compressor at __________ velocity (without effecting the mass of air to flow and velocity of flow) is known as prewhirl.
Options- A. reduced
- B. increased Discuss
- 3. The pressure of air at the beginning of the compression stroke is __________ the atmospheric pressure.
Options- A. equal to
- B. less than
- C. more than Discuss
- 4. In a single stage, single acting reciprocating air compressor, without clearance, the workdone on the air during isentropic compression is __________ the heat required to raise the temperature of air from T1 to T2 at a constant pressure.
Options- A. equal to
- B. less than
- C. greater than Discuss
- 5. Which of the following statement is correct relating to rocket engines?
Options- A. The combustion chamber in a rocket engine is directly analogous to the reservoir of a super sonic wind tunnel
- B. The stagnation conditions exist at the combustion chamber
- C. The exit velocities of exhaust gases are much higher than those in jet engine
- D. all of the above Discuss
- 6. The mass of gas turbine per kW developed is about __________ as that of an I.C. engine.
Options- A. same
- B. one-half
- C. one-fourth
- D. one-sixth Discuss
- 7. In a turbo jet engine, subsequent to heat addition to compressed air, to get the power output, the working substance is expanded in
Options- A. exit nozzle, which is a constant volume process
- B. exit nozzle, which is essentially an isentropic process
- C. turbine blades, which is a constant volume process
- D. turbine blades, which is essentially an isentropic process Discuss
- 8. The performance of air compressor at high altitudes will be __________ as compared to that at sea level.
Options- A. same
- B. lower
- C. higher Discuss
- 9. The intercooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p1 = Intake pressure of air, p2 = Intercooler pressure, and p3 = Delivery pressure of air)
Options- A. p2 = p1 x p3
- B. p2 = p1/p3
- C. p2 = p1 x p3
- D. p2 = p3/p1 Discuss
- 10. In a centrifugal compressor, the air enters the impeller axially and leaves the vane radially.
Options- A. Yes
- B. No Discuss
Compressors, Gas Dynamics and Gas Turbines problems
Search Results
Correct Answer: low frontal area
Correct Answer: reduced
Correct Answer: less than
Correct Answer: equal to
Correct Answer: all of the above
Correct Answer: one-sixth
Correct Answer: turbine blades, which is essentially an isentropic process
Correct Answer: lower
Correct Answer: p2 = p1 x p3
Correct Answer: No
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