Practice Test: Question Set - 01
1. If the flow of air through the compressor is perpendicular to its axis, then it is a
- (A) Reciprocating
compressor
- (B) Centrifugal
compressor
- (C) Axial flow
compressor
- (D) Turbo
compressor
2. Gas turbines use following type of air compressor
- (A) Centrifugal type
- (B) Reciprocating type
- (C) Lobe type
- (D) Axial flow type
3. The gas in cooling chamber of a closed cycle gas turbine is cooled at
- (A) Constant
volume
- (B) Constant
temperature
- (C) Constant
pressure
- (D) None of
these
4. The maximum combustion pressure in gas turbine as compared to I.C. engine is
- (A) More
- (B) Less
- (C) Same
- (D) Depends on other factors
5. In a closed cycle gas turbine, the air is compressed
- (A) Isothermally
- (B) Polytropically
- (C) Isentropically
- (D) None of
these
6. The closed cycle in gas turbines
- (A) Provides greater flexibility
- (B) Provides lesser flexibility
- (C) In never used
- (D) Is used when gas is to be burnt
7. The overall thermal efficiency of an ideal gas turbine plant is (where r = Pressure ratio)
- (A) r ɣ-1
- (B) 1 - r ɣ-1
- (C) 1 - (1/r) ɣ-1/ɣ
- (D) 1 - (1/r) ɣ/ɣ-1
8. Pick up the correct statement
- (A) Large gas turbines use radial inflow
turbines
- (B) Gas turbines have their blades similar to
steam turbine
- (C) Gas turbine's blade will appear as impulse
section at the hub and as a reaction section at tip
- (D) Gas turbines use both air and liquid
cooling
9. The degree of reaction is usually kept ________ for all types of axial flow compressors.
- (A) 0.2
- (B) 0.3
- (C) 0.4
- (D) 0.5
10. Ram compression in turbojet involves
- (A) Reduction of speed of incoming air and
conversion of part of it into pressure energy
- (B) Compression of inlet air
- (C) Increasing speed of incoming air
- (D) Lost work
11. A compressor mostly used for supercharging of I.C. engines is
- (A) Radial flow
compressor
- (B) Axial flow
compressor
- (C) Roots blower
- (D) Reciprocating
compressor
12. In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of
- (A) Vacuum
- (B) Atmospheric air
- (C) Compressed air
- (D) Oxygen alone
13. The work-done on a compressor will be minimum if air is taken from
- (A) The
atmosphere
- (B) A source at
0° C
- (C) A source of
low temperature air
- (D) A source of
high temperature air
14. In the aircraft propellers
- (A) The propulsive matter is caused to flow
around the propelled body
- (B) Propulsive matter is ejected from within
the propelled body
- (C) Its functioning does not depend on presence
of air
- (D) All of the above
15. In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into
- (A) Atmosphere
- (B) Vacuum
- (C) Discharge
nozzle
- (D) Back to the
compressor
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