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Compressors, Gas Turbines And Jet Engines MCQ
300 Important Compressors, Gas Turbines And Jet Engines MCQ Question and Answer | PDF Free Download
1.In jet engines, paraffin is usually used as the fuel because of its
- AHigh calorific value
- BEase of atomization
- CLow freezing point
- DBoth (A) and (C) above
2.The compressor efficiency is the
- AIsothermal H.P/indicated H.R
- BIsothermal H.P./shaft H.R
- CTotal output/air input
- DCompression work/motor input
3.The air entry velocity m a rocket as compared to aircraft is
- ASame
- BMore
- CLess
- DZero
4.Rotary compressors are used for delivering
- ASmall quantities of air at high pressures
- BLarge quantities of air at high pressures
- CSmall quantities of air at low pressures
- DLarge quantities of air at low pressures
5.Intercooling in gas turbines
- ADecreases net output but increases thermal efficiency
- BIncreases net output but decreases thermal efficiency
- CDecreases net output and thermal efficiency both
- DIncreases net output and thermal efficiency both
6.Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
- ABackward curved blades has poor efficiency
- BBackward curved blades lead to stable performance
- CForward curved blades has higher efficiency
- DForward curved blades produce lower pressure ratio
7.Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
- ABackward curved blades has poor efficiency
- BBackward curved blades lead to stable performance
- CForward curved blades has higher efficiency
- DForward curved blades produce lower pressure ratio
8.The material commonly used for air craft gas turbine is
- AStainless steel
- BHigh alloy steel
- CDuralumin
- DTimken, Haste alloys
9.The degree of reaction is usually kept ________ for all types of axial flow compressors.
- A0.2
- B0.3
- C0.4
- D0.5
10.Propulsive efficiency is defined as ratio of
- AThrust power and fuel energy
- BEngine output and propulsive power
- CPropulsive power and fuel input
- DThrust power and propulsive power
11.When the outlet angle from the rotor of a centrifugal compressor is more than 90°, then the blades are said to be
- AForward curved
- BBackward curved
- CRadial
- DNone of these
12.The temperature of air at the beginning of the compression stroke is ________ the atmospheric temperature.
- AEqual to
- BLess than
- CMore than
- DNone of these
13.The assumption made in two stage compression with inter-cooler is that
- AThere is no pressure drop in the inter-cooler
- BThe compression in both the cylinders is polytropic
- CThe suction and delivery of air takes place at constant pressure
- DAll of the above
14.Euler's equation is applicable for
- ACentrifugal compressor
- BAxial compressor
- CPumps
- DAll of the above
15.The propulsive power of the rocket is (where v₁ = Jet velocity, and v₂ = Aircraft velocity)
- A(v₁² -v₂²)/2g
- B(v₁ - v₂)²/2g
- C(v₁² -v₂²)/g
- D(v₁ - v₂)²/g
16.In a single acting reciprocating air compressor, without clearance, the compression of air may be
- AIsothermal
- BPolytropic
- CIsentropic
- DAny one of these
17.For minimum work in multistage compression, assuming same index of compression in all stages
- AWork done in first stage should be more
- BWork done in subsequent stages should increase
- CWork done in subsequent stages should decrease
- DWork done in all stages should be equal
18.For an irreversible gas turbine cycle, the efficiency and work ratio both depend on
- APressure ratio alone
- BMaximum cycle temperature alone
- CMinimum cycle temperature alone
- DBoth pressure ratio and maximum cycle temperature
19.Maximum work is done in compressing air when the compression is
- AIsothermal
- BAdiabatic
- CPolytropic
- DNone of the above
20.The performance of air compressor at high altitudes will be ________ as compared to that at sea level.
- ASame
- BLower
- CHigher
- DNone of these