Compressors, Gas Turbines and Jet Engines MCQs

Question 1

The compressor efficiency is the

Accepted Answer

Isothermal H.P/indicated H.R

Answer

Isothermal H.P./shaft H.R

Answer

Total output/air input

Answer

Compression work/motor input

Question 2

In jet engines, paraffin is usually used as the fuel because of its

Accepted Answer

Both (A) and (C) above

Answer

High calorific value

Answer

Ease of atomisation

Answer

Low freezing point

Question 3

In air compressors, free air delivery means the

Accepted Answer

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

Answer

Volume of air delivered by the compressor

Answer

Volume of air sucked by the compressor during its suction stroke

Answer

None of the above

Question 4

Which of the following statement is correct?

Accepted Answer

The compression ratio for the compressor is always greater than unity

Answer

The ratio of the discharge pressure to the inlet pressure of air is called compressor efficiency

Answer

The compressor capacity is the ratio of work-done per cycle to the stroke volume

Answer

During isothermal compression of air, the work-done in a compressor is maximum

Question 5

Which of the following statement is correct?

Accepted Answer

Both (A) and (B)

Answer

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

Answer

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

Answer

None of these

Question 6

The assumption made in two stage compression with inter-cooler is that

Accepted Answer

All of the above

Answer

There is no pressure drop in the inter-cooler

Answer

The compression in both the cylinders is polytropic

Answer

The suction and delivery of air takes place at constant pressure

Question 7

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

Accepted Answer

More than

Answer

Equal to

Answer

Less than

Answer

None of these

Question 8

When the outlet angle from the rotor of a centrifugal compressor is more than 90°, then the blades are said to be

Accepted Answer

Forward curved

Answer

Backward curved

Answer

Radial

Answer

None of these

Question 9

The volumetric efficiency of compressor with increase in compression ratio will

Accepted Answer

Decrease

Answer

Increase

Answer

Remain same

Answer

May increase or decrease depending on clearance volume