Compressors, Gas Turbines And Jet Engines MCQs

Option A: centrifugal pump

Option B: reciprocating pump

Option C: turbine

Option D: sliding vane compressor

Correct Answer: turbine ✔

Option A: 1.03 kg/cm2

Option B: 1.06 kg/cm2

Option C: 1.00 kg/cm2

Option D: 0.53 kg/cm2

Correct Answer: 1.00 kg/cm2 ✔

Option A: larger air handling ability per unit frontal area

Option B: higher pressure ratio per stage

Option C: aerofoil blades are used

Option D: higher average velocities

Correct Answer: larger air handling ability per unit frontal area ✔

Option A: 6 kg/cm2

Option B: 10 kg/cm2

Option C: 16 kg/cm2

Option D: 25 kg/cm2

Correct Answer: 10 kg/cm2 ✔

Option A: isothermal compression

Option B: adiabatic compression

Option C: isentropic compression

Option D: polytropic compression

Correct Answer: adiabatic compression ✔

Option A: air stream blocking the passage

Option B: motion of air at sonic velocity

Option C: unsteady, periodic and reversed flow

Option D: air stream not able to follow the blade contour

Correct Answer: unsteady, periodic and reversed flow ✔

Option A: 1 : 1.2

Option B: 1 : 2

Option C: 1 : 5

Option D: 1 : 10

Correct Answer: 1 : 1.2 ✔

Option A: compressor efficiency

Option B: isentropic efficiency

Option C: Euler’s efficiency

Option D: pressure coefficient

Correct Answer: pressure coefficient ✔

Option A: slip factor

Option B: velocity factor

Option C: velocity coefficient

Option D: blade effectiveness

Correct Answer: slip factor ✔

Option A: 2 kg/cm2

Option B: 6 kg/cm2

Option C: 10 kg/cm2

Option D: 14.7 kg/cm2

Correct Answer: 2 kg/cm2 ✔

Option A: better lubrication is possible advantages of multistage

Option B: more loss of air due to leakage past the cylinder

Option C: mechanical balance is better

Option D: air can be cooled perfectly in between

Correct Answer: more loss of air due to leakage past the cylinder ✔

Option A: inlet losses

Option B: impeller channel losses

Option C: diffuser losses

Option D: all of the above

Correct Answer: all of the above ✔

Option A: increase

Option B: decrease

Option C: remain unaffected

Option D: other factors control it

Correct Answer: increase ✔

Option A: isentropic compression

Option B: isothermal compression

Option C: polytropic compression

Option D: any one of the above

Correct Answer: isentropic compression ✔

Option A: 0.1%

Option B: 0.5%

Option C: 1%

Option D: 5%

Correct Answer: 1% ✔

Option A: work done in first stage should be more

Option B: work done in subsequent stages should increase

Option C: work done in subsequent stages should decrease

Option D: work done in all stages should be equal

Correct Answer: work done in all stages should be equal ✔

Option A: less power requirement

Option B: better mechanical balance

Option C: less loss of air due to leakage past the cylinder

Option D: more effective lubrication

Correct Answer: lower volumetric efficiency ✔

Option A: centrifugal

Option B: reciprocating

Option C: axial

Option D: screw

Correct Answer: reciprocating ✔

Option A: increase velocity

Option B: make the flow stream-line

Option C: convert pressure energy into kinetic energy

Option D: convert kinetic energy into pressure energy

Correct Answer: convert kinetic energy into pressure energy ✔

Option A: no flow of air

Option B: fixed mass flow rate regardless of pressure ratio

Option C: reducing mass flow rate with increase in pressure ratio

Option D: increased inclination of chord with air steam

Correct Answer: fixed mass flow rate regardless of pressure ratio ✔

Option A: pressure coefficient

Option B: work coefficient

Option C: polytropic reaction

Option D: slip factor

Correct Answer: pressure coefficient ✔

Option A: directly proportional to clearance volume

Option B: greatly affected by clearance volume

Option C: not affected by clearance volume

Option D: inversely proportional to clearance volume

Correct Answer: not affected by clearance volume ✔

Option A: increase

Option B: decrease

Option C: remain unaffected

Option D: may increase/decrease depending on compressor clearance

Correct Answer: decrease ✔

Option A: lower power consumption per unit of air delivered

Option B: higher volumetric efficiency

Option C: decreased discharge temperature

Option D: moisture free air

Correct Answer: all of the above ✔

Option A: N.T.P. conditions

Option B: intake temperature and pressure conditions

Option C: 0°C and 1 kg/cm2

Option D: 20°C and 1 kg/cm2

Correct Answer: intake temperature and pressure conditions ✔

Option A: 0.1%

Option B: 0.5%

Option C: 1.0%

Option D: 5%

Correct Answer: 1.0% ✔

Option A: start-stop motor

Option B: constant speed unloader

Option C: relief valve

Option D: variable speed

Correct Answer: start-stop motor ✔

Option A: volume of air inhaled at working conditions

Option B: volume of air inhaled at N.T.P. conditions

Option C: volume at 0°C and 1 kg/cm2

Option D: volume at 20°C and 1 kg/cm2

Correct Answer: volume of air inhaled at N.T.P. conditions ✔

Option A: poppet valve

Option B: mechanical valve of the corliss, sleeve, rotary or semirotary type

Option C: disc or feather type

Option D: any of the above

Correct Answer: disc or feather type ✔

Option A: isothermal H.P/indicated H.R

Option B: isothermal H.P./shaft H.R

Option C: total output/air input

Option D: compression work/motor input

Correct Answer: isothermal H.P/indicated H.R ✔

Option A: isentropic

Option B: isothermal

Option C: polytropic

Option D: somewhere in between isentropic and isothermal

Correct Answer: isothermal ✔

Option A: top side of main

Option B: bottom side of main

Option C: left side of main

Option D: right side of main

Correct Answer: top side of main ✔

Option A: rise gradually towards the point of use

Option B: drop gradually towards the point of use

Option C: be laid vertically

Option D: be laid exactly horizontally

Correct Answer: drop gradually towards the point of use ✔

Option A: less

Option B: more

Option C: same

Option D: more/less depending on compressor capacity

Correct Answer: more ✔

Option A: radial component

Option B: axial component

Option C: tangential component

Option D: resultant component

Correct Answer: axial component ✔

Option A: more power

Option B: less power

Option C: same power

Option D: more/less power depending on other factors

Correct Answer: less power ✔

Option A: conversion of pressure energy into kinetic energy

Option B: conversion of kinetic energy into pres¬sure energy

Option C: centripetal action

Option D: generating pressure directly

Correct Answer: conversion of kinetic energy into pres¬sure energy ✔

Option A: same

Option B: higher

Option C: lower

Option D: dependent on other factors

Correct Answer: lower ✔

Option A: start-stop motor

Option B: constant speed unloader

Option C: relief valve

Option D: variable speed

Correct Answer: constant speed unloader ✔

Option A: throttle control B. clearance control

Option B: blow-off control

Option C: any one of the above

Option D: none of the above

Correct Answer: any one of the above ✔

Option A: before intercooler

Option B: after intercooler

Option C: after receiver

Option D: between after-cooler and air receiver

Correct Answer: between after-cooler and air receiver ✔

Option A: A.C. electric motor

Option B: compressed air

Option C: petrol engine

Option D: diesel engine

Correct Answer: compressed air ✔

Option A: employing intercooler

Option B: by constantly cooling the cylinder

Option C: by running compressor at very slow speed

Option D: by insulating the cylinder

Correct Answer: by running compressor at very slow speed ✔

Option A: lowest

Option B: highest

Option C: anything.

Option D: atmospheric

Correct Answer: atmospheric ✔

Option A: large quantity of air at high pressure

Option B: small quantity of air at high pressure

Option C: small quantity of air at low pressure

Option D: large quantity of air at low pressure

Correct Answer: large quantity of air at high pressure ✔

Option A: cool the air

Option B: decrease the delivery temperature for ease in handling

Option C: cause moisture and oil vapour to drop out

Option D: reduce volume

Correct Answer: cause moisture and oil vapour to drop out ✔

Option A: large quantity of air at high pressure

Option B: small quantity of air at high pressure

Option C: small quantity of air at low pressure

Option D: large quantity of air at low pressure

Correct Answer: small quantity of air at high pressure ✔

Option A: These are used to dampen pulsations ,

Option B: These act as reservoir to- take care of sudden demands

Option C: These increase compressor efficiency

Option D: These knock out some oil and moisture

Correct Answer: These increase compressor efficiency ✔

Option A: it allows maximum compression to be achieved

Option B: it greatly affects volumetric efficiency

Option C: it results in minimum work

Option D: it permits isothermal compression

Correct Answer: it greatly affects volumetric efficiency ✔

Option A: compressor efficiency

Option B: isothermal efficiency

Option C: volumetric efficiency

Option D: mechanical efficiency

Correct Answer: mechanical efficiency ✔

Option A: centrifugal compressor

Option B: axial compressor

Option C: pumps

Option D: all of the above

Correct Answer: all of the above ✔

Option A: Power consumption per unit of air delivered is low

Option B: Volumetric efficiency is high

Option C: It is best suited for compression ratios around 7:1

Option D: The moisture in air is condensed in the intercooler

Correct Answer: Volumetric efficiency is high ✔

Option A: from an air conditioned room maintained at 20°C

Option B: from outside atmosphere at 1°C

Option C: from coal yard side

Option D: from a side where cooling tower is located nearby

Correct Answer: from a side where cooling tower is located nearby ✔

Option A: increases with increase in compression ratio

Option B: decreases with increase in compression ratio

Option C: in not dependent upon compression ratio

Option D: may increase/decrease depending on compressor capacity

Correct Answer: decreases with increase in compression ratio ✔

Option A: to accommedate Valves in the cylinder head

Option B: to provide cushioning effect

Option C: to attain high volumetric efficiency

Option D: to avoid mechanical bang of piston with cylinder head

Correct Answer: to provide cushioning effect ✔

Option A: increases

Option B: decreases

Option C: remains same

Option D: increases/decreases depending on com-pressor capacity

Correct Answer: remains same ✔

Option A: compression index

Option B: compression ratio

Option C: compressor efficiency

Option D: mean effective pressure

Correct Answer: mean effective pressure ✔

Option A: gauge discharge pressure to the gauge intake pressure

Option B: absolute discharge pressure to the ab-solute intake pressure

Option C: pressures at discharge and suction cor-responding to same temperature

Option D: stroke volume and clearance volume

Correct Answer: absolute discharge pressure to the ab-solute intake pressure ✔

Option A: the ratio of stroke volume to clearance volume

Option B: the ratio of the air actually delivered to the amount of piston displacement

Option C: reciprocal of compression ratio

Option D: index of compressor performance

Correct Answer: the ratio of the air actually delivered to the amount of piston displacement ✔

Option A: increases with increase in compression ratio

Option B: decreases with increase in compression ratio

Option C: is not dependent upon compressin ratio

Option D: may increase/decrease depending on compressor capacity

Correct Answer: is not dependent upon compressin ratio ✔

Option A: 20-30%

Option B: 40-50%

Option C: 60-70%

Option D: 70-90%

Correct Answer: 70-90% ✔

Option A: as large as possible

Option B: as small as possible

Option C: about 50% of swept volume

Option D: about 100% of swept volume

Correct Answer: as small as possible ✔

Option A: mechanical efficiency

Option B: volumetric efficiency

Option C: isothermal efficiency

Option D: adiabatic efficiency

Correct Answer: mechanical efficiency ✔

Option A: radial flow

Option B: axial flow

Option C: centrifugal

Option D: combination of above

Correct Answer: axial flow ✔

Option A: ideal compression

Option B: adiabatic compression

Option C: botii isothermal and adiabatic compression

Option D: isentropic compression

Correct Answer: isothermal compression ✔

Option A: one adiabatic, two isobaric, and one constant volume

Option B: two adiabatic and two isobaric

Option C: two adiabatic, one isobaric and one constant volume,

Option D: one adiabatic, one isobaric and two constant volume

Correct Answer: two adiabatic and two isobaric ✔

Option A: 1

Option B: 1.2 ,

Option C: 1.3

Option D: 1.4

Correct Answer: 1 ✔

Option A: one adiabatic, two isobaric, and one constant volume

Option B: two adiabatic and two isobaric

Option C: two adiabatic, one isobaric and one constant volume

Option D: one adiabatic, one isobaric and two constant volume

Correct Answer: one adiabatic, two isobaric, and one constant volume ✔

Option A: 3 m3/mt

Option B: 1.5 m3/mt

Option C: 18 m3/mt

Option D: 6 m3/mt

Correct Answer: 3 m3/mt ✔

Option A: ityrequires very big cylinder

Option B: it does not increase pressure much

Option C: it is impossible in practice

Option D: compressor has to run at very slow speed to achieve it

Correct Answer: compressor has to run at very slow speed to achieve it ✔

Option A: cools the delivered air

Option B: results in saving of power in compressing a given volume to given pressure

Option C: is the standard practice for big compressors

Option D: enables compression in two stages

Correct Answer: results in saving of power in compressing a given volume to given pressure ✔

Option A: increases

Option B: decreases

Option C: remains unaffected

Option D: may increase or decrease depending on compressor capacity

Correct Answer: increases ✔

Option A: atmospheric conditions at any specific location

Option B: 20°C and 1 kg/cm2 and relative humidity 36%

Option C: 0°C and standard atmospheric conditions

Option D: 15°C and 1 kg/cm2

Correct Answer: 20°C and 1 kg/cm2 and relative humidity 36% ✔

Option A: isothermal

Option B: adiabatic

Option C: polytropic

Option D: any one of the above

Correct Answer: adiabatic ✔

Option A: standard air

Option B: free air

Option C: compressed air

Option D: compressed air at delivery pressure

Correct Answer: free air ✔

Option A: atmospheric conditions at any specific location

Option B: 20°C and 1 kg/cm2 and relative humidity of 36%

Option C: 0°C and standard atmospheric conditions

Option D: 15°C and 1 kg/cm2

Correct Answer: atmospheric conditions at any specific location ✔

Option A: 0.5 kg

Option B: 1.0 kg

Option C: 1.3 kg

Option D: 2.2 kg

Correct Answer: 1.3 kg ✔

Option A: isothermal h.p. to the BHP of motor

Option B: isothermal h.p. to adiabatic h.p.

Option C: power to drive compressor to isothermal h.p.

Option D: work to compress air isothermally to work for actual compression

Correct Answer: isothermal h.p. to the BHP of motor ✔

Option A: multi-stage compression

Option B: cold water spray

Option C: both A. and B. above

Option D: fully insulating the cylinder

Correct Answer: C. both A. and B. above ✔

Option A: at very high speed

Option B: at very slow speed

Option C: at average speed

Option D: at zero speed

Correct Answer: at very slow speed ✔

Option A: isothermally

Option B: adiabatically

Option C: isentropically

Option D: isochronically

Correct Answer: isothermally ✔

Option A: temperature during compression remains constant

Option B: no heat leaves or enters the compressor cylinder during cornpression

Option C: temperature rise follows a linear relationship

Option D: work done is maximum

Correct Answer: no heat leaves or enters the compressor cylinder during cornpression ✔