Compressors, Gas Turbines and Jet Engines - Set 06 - ObjectiveBooks

# Compressors, Gas Turbines and Jet Engines - Set 06

### Practice Test: Question Set - 06

1. The capacity of a compressor is expressed in
(A) kg/m²
(B) kg/m³
(C) m³/min
(D) m³/kg

2. The work done per unit mass of air in compression will be least when 'n' is equal to
(A) 1
(B) 1.2
(C) 1.3
(D) 1.4

3. Cylinder clearance in a compressor should be
(A) As large as possible
(B) As small as possible
(C) About 50% of swept volume
(D) About 100% of swept volume

4. The ratio of work-done per cycle to the stroke volume of the compressor is known as
(A) Compressor capacity
(B) Compression ratio
(C) Compressor efficiency
(D) Mean effective pressure

5. Ratio of compression is the ratio of
(A) Gauge discharge pressure to the gauge intake pressure
(B) Absolute discharge pressure to the absolute intake pressure
(C) Pressures at discharge and suction corresponding to same temperature
(D) Stroke volume and clearance volume

6. The compressed air may be used
(A) In gas turbine plants
(B) For operating pneumatic drills
(C) In starting and supercharging of I.C. engines
(D) All of the above

7. The net work input required for compressor with increase in clearance volume
(A) Increases
(B) Decreases
(C) Remains same
(D) Increases/decreases depending on compressor capacity

8. For minimum work required to compress and deliver a quantity of air by multistage compression
(A) The compression ratio in each stage should be same
(B) The intercooling should be perfect
(C) The work-done in each stage should be same
(D) All of the above

9. Ratio of indicated h.p. to shaft h.p. in known as
(A) Compressor efficiency
(B) Isothermal efficiency
(C) Volumetric efficiency
(D) Mechanical efficiency

10. In a jet engine, the air-fuel ratio is
(A) 30:1
(B) 40:1
(C) 50:1
(D) 60:1

11. Volumetric efficiency is
(A) The ratio of stroke volume to clearance volume
(B) The ratio of the air actually delivered to the amount of piston displacement
(C) Reciprocal of compression ratio
(D) Index of compressor performance

12. In axial flow compressor, exit flow angle deviation from the blade angle is a function of
(B) Blade camber and incidence angle
(C) Space-chord ratio
(D) Blade camber and space-chord ratio

13. Volumetric efficiency of air compressors is of the order of
(A) 20 - 30%
(B) 40 - 50%
(C) 60 - 70%
(D) 70 - 90%

14. The velocity of air entering in a rocket is _________ as compared to an aircraft.
(A) Zero
(B) Less
(C) More
(D) Same

15. Volumetric efficiency of a compressor with clearance volume
(A) Increases with increase in compression ratio
(B) Decreases with increase in compression ratio
(C) In not dependent upon compression ratio
(D) May increase/decrease depending on compressor capacity

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