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4

Actual compression curve is

A. Same as isothermal

B. Same as adiabatic

C. Better than isothermal and adiabatic

D. In between isothermal and adiabatic

Correct Answer :

D. In between isothermal and adiabatic


Related Questions

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4

Ratio of indicated h.p. to shaft h.p. in known as

A. Compressor efficiency

B. Isothermal efficiency

C. Volumetric efficiency

D. Mechanical efficiency

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4

The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation

A. 0.1 %

B. 0.5 %

C. 1.0 %

D. 5 %

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4

The specific output per kg mass flow rate of a gas turbine (having fixed efficiencies of compressor and turbine and fixed higher and lower temperature) with increase in pressure ratio will

A. Increase first at fast rate and then slow

B. Increase first at slow rate and then fast

C. Decrease continuously

D. First increase, reach maximum and then decrease

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4

Fighter bombers use following type of engine

A. Turbojet

B. Turbo-propeller

C. Rocket

D. Ramjet

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4

The efficiency and work ratio of a gas turbine plant can be increased by

A. Adding heat exchanger

B. Injecting water in/around combustion chamber

C. Reheating the air after partial expansion in the turbine

D. All of the above

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4

What will be the volume of air at 327°C if its volume at 27°C is 1.5 m³/ mt?

A. 3 m³/ mt.

B. 1.5 m³/ mt.

C. 18 m³/ mt.

D. 6 m³/ mt.

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4

An ideal air compressor cycle without clearance on PV diagram can be represented by following processes

A. One adiabatic, two isobaric, and one constant volume

B. Two adiabatic and two isobaric

C. Two adiabatic, one isobaric and one constant volume

D. One adiabatic, one isobaric and two constant volumes

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4

Ratio of indicated H.P. and brake H.P. is known as

A. Mechanical efficiency

B. Volumetric efficiency

C. Isothermal efficiency

D. Adiabatic efficiency

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4

In turbo fan engine, the jet velocity as compared to turbojet engine is

A. Less

B. More

C. Same

D. May be less or more depending upon speed

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4

In a turbo jet engine, subsequent to heat addition to compressed air, to get the power output, the working substance is expanded in

A. Exit nozzle, which is a constant volume process

B. Exit nozzle, which is essentially an isentropic process

C. Turbine blades, which is a constant volume process

D. Turbine blades, which is essentially an isentropic process

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4

The intercooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p₁ = Intake pressure of air, p₂ = Intercooler pressure, and p₃ = Delivery pressure of air)

A. p₂ = p₁ × p₃

B. p₂ = p₁/p₃

C. p₂ = p₁ × p₂

D. p₂ = p₃/p₁

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4

The thrust of a jet propulsion power unit can be increased by

A. Injecting water into the compressor

B. Burning fuel after gas turbine

C. Injecting ammonia into the combustion chamber

D. All of the above

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4

In an axial flow compressor, the ratio of pressure in the rotor blades to the pressure rise in the compressor in one stage is known as

A. Work factor

B. Slip factor

C. Degree of reaction

D. Pressure coefficient

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4

For speed above 3000 km/hour, it is more advantageous to use

A. Turbojet engine

B. Ramjet engine

C. Propellers

D. Rockets

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4

The efficiency of a jet engine is higher at

A. Low speeds

B. High speeds

C. Low altitudes

D. High altitudes

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4

The axial flow compressor is preferred in aircraft gas turbines because of

A. Low frontal area

B. Higher thrust

C. High pressure rise

D. None of these

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4

The maximum compression ratio in an actual single stage axial flow compressor is of the order of

A. 1 : 1.2

B. 1 : 2

C. 1 : 5

D. 1 : 10

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4

Rotary compressors are used for delivering

A. Small quantities of air at high pressures

B. Large quantities of air at high pressures

C. Small quantities of air at low pressures

D. Large quantities of air at low pressures

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4

During base load operation, the best method of controlling compressor is

A. Start-stop motor

B. Constant speed unloader

C. Relief valve

D. Variable speed

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4

The pressure of air at the beginning of the compression stroke is ________ the atmospheric pressure.

A. Equal to

B. Less than

C. More than

D. None of these

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4

The ratio of the net work obtained from the gas turbine plant to the turbine work is known as

A. Compression ratio

B. Work ratio

C. Pressure ratio

D. None of these

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4

Reheating in a multistage expansion gas turbine __________ compressor work.

A. Has no effect on

B. Decreases

C. Increases

D. None of these

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4

In air compressors, free air delivery means the

A. Actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions

B. Volume of air delivered by the compressor

C. Volume of air sucked by the compressor during its suction stroke

D. None of the above

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4

Air-fuel ratio in a jet engine will be of the order of

A. 10 : 1

B. 15 : 1

C. 20 : 1

D. 60 : 1

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4

The overall isothermal efficiency of compressor is defined as the ratio of

A. Isothermal h.p. to the BHP of motor

B. Isothermal h.p. to adiabatic h.p.

C. Power to drive compressor to isothermal h.p.

D. Work to compress air isothermally to work for actual compression

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4

Stalling of blades in axial flow compressor is the phenomenon of

A. Air stream blocking the passage

B. Motion of air at sonic velocity

C. Unsteady periodic and reversed flow

D. Air stream not able to follow the blade contour

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4

The work ratio of a gas turbine plant is defined as the ratio of

A. Net work output and heat supplied

B. Net work output and work done by turbine

C. Actual heat drop and isentropic heat drop

D. Net work output and isentropic heat drop

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4

The ratio of isentropic work to Eulers work is known as

A. Compressor efficiency

B. Isentropic efficiency

C. Euler's efficiency

D. Pressure coefficient

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4

In which case the air-fuel ratio is likely to be maximum?

A. Gas turbine

B. 4-stroke petrol engine

C. 4-stroke diesel engine

D. Multi cylinder engine

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4

In a four stage compressor, if the pressure at the first and third stage is 1 bar and 16 bar, then the delivery pressure at the fourth stage will be

A. 1 bar

B. 16 bar

C. 64 bar

D. 256 bar