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Compressors, Gas Dynamics and Gas Turbines MCQ

1. A rocket works with maximum overall efficiency when air-craft velocity is __________ the jet velocity.

Equal to

One-half

Double

Answer

Correct Answer: One-half

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2. Intercooling in gas turbines

Decreases net output and thermal efficiency both

Increases net output and thermal efficiency both

Increases net output but decreases thermal efficiency

Decreases net output but increases thermal efficiency

Answer

Correct Answer: Increases net output and thermal efficiency both

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3. The maximum temperature in a gas turbine is

500°C

200°C

700°C

1000°C

Answer

Correct Answer: 700°C

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4. Which of the following statement is correct?

The ratio of the discharge pressure to the inlet pressure of air is called compressor efficiency.

The compression ratio for the compressor is always greater than unity.

The compressor capacity is the ratio of workdone per cycle to the stroke volume.

During isothermal compression of air, the workdone in a compressor is maximum.

Answer

Correct Answer: The compression ratio for the compressor is always greater than unity.

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5. Rotary compressors are used for delivering

Small quantities of air at high pressures

Small quantities of air at low pressures

Large quantities of air at high pressures

Large quantities of air at low pressures

Answer

Correct Answer: Large quantities of air at low pressures

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6. An open cycle gas turbine works on the same cycle as that of a closed cycle gas turbine.

Yes

Answer

Correct Answer: Yes

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7. In a reciprocating air compressor, the compression work per kg of air

Increases as clearance volume increases

Is independent of clearance volume

Increases as clearance volume decreases

Decreases as clearance volume increases

Answer

Correct Answer: Is independent of clearance volume

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8. Gas turbine as compared to steam turbine

Requires less space for installation

Has less efficiency

Has compressor and combustion chamber

All of these

Answer

Correct Answer: All of these

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9. When the temperature of air leaving the intercooler, in a two stage compression with intercooler, is __________ the original atmospheric air temperature, then the intercooling is known as perfect or complete intercooling.

More than

Equal to

Less than

Answer

Correct Answer: Equal to

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10. The rotary compressors are suitable for large discharge of air at low pressure.

False

True

Answer

Correct Answer: True

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11. Which of the following statement is wrong?

The ratio of the volume of free air delivery per stroke to the swept volume of the piston is called volumetric efficiency.

The minimum work required for a two stage reciprocating air compressor is double the work required for each stage.

In a two stage reciprocating air compressor with complete intercooling, maximum work is saved.

None of these

Answer

Correct Answer: None of these

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12. The type of rotary compressor used in gas turbines, is of

Axial flow type

Radial flow type

Centrifugal type

None of these

Answer

Correct Answer: Axial flow type

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13. 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.

False

True

Answer

Correct Answer: True

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14. The compression ratio in a gas turbine is

Answer

Correct Answer: 1

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15. The stagnation pressure rise in a centrifugal compressor takes place

In the impeller only

In the inlet guide vanes only

In the diffuser and impeller

In the diffuser only

Answer

Correct Answer: In the diffuser and impeller

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16. The capacity of a compressor is expressed in

M3/min

Kg/m2

M3/kg

Kg/m3

Answer

Correct Answer: M3/min

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17. The actual volume of air delivered by a compressor, When reduced to the normal temperature and pressure conditions is called compressor capacity.

Yes

Answer

Correct Answer: No

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18. A large clearance Volume in a reciprocating compressor results in

Increased volume flow rate

Lower delivery pressure

Lower suction pressure

Reduced volume flow rate

Answer

Correct Answer: Reduced volume flow rate

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19. The increase in pressure in a roots blower is entirely due to back flow of air.

Disagree

Agree

Answer

Correct Answer: Agree

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20. In axial flow compressor, exit flow angle deviation from the blade angle is a function of

Blade camber and incidence angle

Space-chord ratio

Blade camber and space-chord ratio

Blade camber

Answer

Correct Answer: Blade camber and incidence angle

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Mechanical Engineering MCQs | Topic-wise

MCQ on Automobile Engineering	MCQ on Compressors, Gas Dynamics and Gas Turbines
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MCQ on IC Engines and Nuclear Power Plants	MCQ on Manufacturing Engineering (Mechanical Engineering)
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