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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.Gas turbine as compared to internal combustion engine
- ACan be driven at a very high speed
- BProduces uniform torque
- CHas more efficiency
- DAll of these
2.In a turbo jet engine, subsequent to heat addition to compressed air, to get the power output, the working substance is expanded in
- AExit nozzle, which is a constant volume process
- BExit nozzle, which is essentially an isentropic process
- CTurbine blades, which is a constant volume process
- DTurbine blades, which is essentially an isentropic process
3.The gas in cooling chamber of a closed cycle gas turbine is cooled at
- AConstant volume
- BConstant temperature
- CConstant pressure
- DNone of these
4.Work ratio of a gas turbine may be improved by
- ADecreasing the compression work
- BIncreasing the compression work
- CIncreasing the turbine work
- DBoth (A) and (C) above
5.The velocity of air entering in a rocket is _________ as compared to an aircraft.
- AZero
- BLess
- CSame
- DMore
6.An air receiver is to be placed outside. Should it be placed in
- ASun
- BShade
- CRain
- DEnclosed room
7.High air-fuel ratio is used in gas turbines
- ATo increase the output
- BTo increase the efficiency
- CTo save fuel
- DTo reduce the exit temperature
8.The working fluid in a turbine is
- AIn two phases
- BIn three phases
- CIn a single phase
- DIn the form of air and water mixture
9.The minimum work required for a three stage reciprocating air compressor is ________ the work required for each stage.
- AEqual to
- BDouble
- CThree times
- DSix times
10.After-cooler is used to
- ARemove impurities from air
- BReduce volume of air
- CCause moisture and oil vapour to drop out
- DCool the air
11.The mean effective pressure of the compressor is the
- AActual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions
- BVolume of air delivered by the compressor
- CVolume of air sucked by the compressor during its suction stroke
- DNone of the above
12.In jet engines the products of combustion after passing through the gas turbine are discharged into
- AAtmosphere
- BBack to the compressor
- CDischarge nozzle
- DVacuum
13.In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into
- AAtmosphere
- BVacuum
- CDischarge nozzle
- DBack to the compressor
14.A compressor at high altitudes will require ________ power.
- ASame
- B`Less
- CMore
- DNone of these
15.The efficiency of the vane blower is (where W₁ = Workdone due to compression, and W₂ = Workdone due to back flow)
- AW₁/(W₁ + W₂)
- BW₂/(W₁ + W₂)
- C(W₁ + W₂)/W₁
- D(W₁ + W₂)/W₂
16.In open cycle turbojet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the
- AThrust and range of aircraft
- BEfficiency of the engine
- CBoth (A) and (B)
- DNone of these
17.In gas turbines, high thermal efficiency is obtained in
- AClosed cycle
- BOpen cycle
- CBoth of the above
- DClosed/open depending on other considerations
18.The compressor capacity with decrease in suction temperature
- AIncreases
- BDecreases
- CRemain unaffected
- DMay increase or decrease depending on compressor capacity
19.A gas turbine used in air craft should have
- AHigh h.p. and low weight
- BLow weight and small frontal area
- CSmall frontal area and high h.p.
- DHigh speed and high h.p.
20.Air-fuel ratio in a jet engine will be of the order of
- A10: 1
- B15: 1
- C20: 1
- D60: 1