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What is the correct answer?

4

The clearance volume of the air compressor is kept minimum because

A. It allows maximum compression to be achieved

B. It greatly affects volumetric efficiency

C. It results in minimum work

D. It permits isothermal compression

Correct Answer :

B. It greatly affects volumetric efficiency


Related Questions

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4

Inter-cooling in gas turbine results in

A. Increase in net output but decrease in thermal efficiency

B. Increase in thermal efficiency but decrease in net output

C. Increase in both thermal efficiency and net output

D. Decrease in both thermal efficiency and net output

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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

Atmospheric pressure is 1.03 kg/cm and vapour pressure is 0.03 kg/cm. The air pressure will be

A. 1.03 kg/cm²

B. 1.06 kg/cm²

C. 1.00 kg/cm²

D. 0.53 kg/cm²

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4

As the turbine inlet temperature increases, the thermal efficiency of gas turbine for the optimum pressure ratio

A. Increases

B. Decreases

C. Remain same

D. First increases and then decreases

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4

Work ratio of a gas turbine may be improved by

A. Decreasing the compression work

B. Increasing the compression work

C. Increasing the turbine work

D. Both (A) and (C) above

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4

Reciprocating air compressor is best suited for

A. Large quantity of air at high pressure

B. Small quantity of air at high pressure

C. Small quantity of air at low pressure

D. Large quantity of air at low pressure

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4

The thrust on the rotor in a centrifugal compressor is produced by

A. Radial component

B. Axial component

C. Tangential component

D. None of the above

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4

The compression ratio in a gas turbine is of the order of

A. 3.5 : 1

B. 5 : 1

C. 8 : 1

D. 12 : 1

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4

The power available for takeoff and climb in case of turbojet engine as compared to reciprocating engine is

A. Less

B. More

C. Same

D. May be less or more depending on ambient conditions

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4

Inter-cooling in multistage compressors is done

A. To cool the air during compression

B. To cool the air at delivery

C. To enable compression in two stages

D. To minimise the work of compression

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4

In the cross compounding of the gas turbine plant

A. H.P. compressor is connected to H.P. turbine and L.P. compressor to L.P. turbine

B. H.P. compressor is connected to L.P. turbine and L.P. compressor is connected to H.P. turbine

C. Both the arrangements can be employed

D. All are connected in series

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4

There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would

A. Remain same

B. Decrease

C. Increase

D. None of the above

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4

The minimum work required for a three stage reciprocating air compressor is ________ the work required for each stage.

A. Equal to

B. Double

C. Three times

D. Six times

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4

Pick up the wrong statement

A. Centrifugal compressors deliver practically constant pressure over a considerable range of capacities

B. Axial flow compressors have a substantially constant delivery at variable pressures

C. Centrifugal compressors have a wider stable operating range than axial flow compressors

D. Axial flow compressors are bigger in diameter compared to centrifugal type

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4

Inter cooling in compressors

A. Cools the delivered air

B. Results in saving of power in compressing a given volume to given pressure

C. Is the standard practice for big compressors

D. Enables compression in two stages

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4

For perfect intercooling in a two stage compressor

A. p₂/p₁ = p₃/p₂

B. p₁/p₃ = p₂/p₁

C. p₁ = p₃

D. p₁ = p₂ p₃

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4

The process, which causes the air to enter the impeller blades of a centrifugal compressor at ________ velocity (without effecting the mass of air to flow and velocity of flow) is known as prewhirl.

A. Reduced

B. Increased

C. Zero

D. None of these

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4

The blades of gas turbine are made of

A. High nickel alloy

B. Stainless steel

C. Carbon steel

D. High alloy steel

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4

Choose the correct statement

A. Gas turbine requires lot of cooling water

B. Gas turbine is capable of rapid start up and loading

C. Gas turbines has flat efficiency at part loads

D. Gas turbines have high standby losses and require lot of maintenance

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4

Propulsion efficiency of the following order is obtained in practice

A. 34 %

B. 50 %

C. 60 %

D. 72 %

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4

Separators in compressor installations are located

A. Before intercooler

B. After intercooler

C. After receiver

D. Between after-cooler and air receiver

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4

Gas turbines use following type of air compressor

A. Centrifugal type

B. Reciprocating type

C. Lobe type

D. Axial flow type

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4

The pressure ratio of an ideal vaned compressor with increase in mass flow rate

A. Increases

B. Decreases

C. Remain constant

D. First decreases and then increases

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4

The ideal efficiency of simple gas turbine cycle depends on

A. Pressure ratio

B. Maximum cycle temperature

C. Minimum cycle temperature

D. All of the above

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4

The velocity of air entering in a rocket is ________ as compared to an aircraft.

A. Zero

B. Less

C. More

D. Same

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4

Which of the following statement is correct?

A. The reciprocating compressors are best suited for high pressure and low volume capacity

B. The effect of clearance volume on power consumption is negligible for the same volume of discharge

C. Both (A) and (B)

D. None of these

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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

The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called

A. Slip factor

B. Velocity factor

C. Velocity coefficient

D. None of the above

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4

The area of actual indicator diagram on an air compressor as compared to area of ideal indicator diagram is

A. Less

B. More

C. Same

D. More/less depending on compressor capacity

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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