Gas Turbines And Jet Engines MCQ

Test your knowledge with important Gas Turbines And Jet Engines MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30+ more Gas Turbines And Jet Engines MCQs on Bissoy. Bissoy App

A closed cycle gas turbine gives ________ efficiency as compared to an open cycle gas turbine.

ক
Same

খ
Lower

গ
Higher

ঘ
None of these
The volumetric efficiency of a compressor

ক
Increases with decrease in compression ratio

খ
Decreases with decrease in compression ratio

গ
Increases with increase in compression ratio

ঘ
Decreases with increase in compression ratio
A rocket works with maximum overall efficiency when air craft velocity is equal to the

ক
Jet velocity

খ
Twice the jet velocity

গ
Half the jet velocity

ঘ
Average of the jet velocity
If the flow of air through the compressor is perpendicular to its axis, then it is a

ক
Reciprocating compressor

খ
Centrifugal compressor

গ
Axial flow compressor

ঘ
Turbo compressor
Mining industry usually employs following motive power

ক
A.C. electric motor

খ
Compressed air

গ
Petrol engine

ঘ
Diesel engine
When air is to be compressed at a high pressure, then it is advantageous to use

ক
Single stage compression

খ
Multistage compression without intercooling

গ
Multistage compression with intercooling

ঘ
None of these
Which is false statement about air receivers?

ক
These are used to dampen pulsations

খ
These act as reservoir to take care of sudden demands

গ
These increase compressor efficiency

ঘ
These knock out some oil and moisture
In turbo fan engine, the jet velocity as compared to turbojet engine is

ক
Less

খ
More

গ
Same

ঘ
May be less or more depending upon speed
Reheating in multistage expansion gas turbine results in

ক
High thermal efficiency

খ
Reduction in compressor work

গ
Decrease of heat loss in exhaust

ঘ
Maximum work output
Reheating in gas turbine results in

ক
Increase of work ratio

খ
Decrease of thermal efficiency

গ
Decrease of work ratio

ঘ
Both (A) and (B) above
Inter-cooling in gas turbine results in

ক
Increase in net output but decrease in thermal efficiency

খ
Increase in thermal efficiency but decrease in net output

গ
Increase in both thermal efficiency and net output

ঘ
Decrease in both thermal efficiency and net output
If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches

ক
Isothermal

খ
Isentropic

গ
Adiabatic

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

ক
Increases

খ
Decreases

গ
Remain same

ঘ
First increases and then decreases
To avoid moisture troubles, the branch connections from compressed air lines should be taken from

ক
Top side of main

খ
Bottom side of main

গ
Left side of main

ঘ
Right side of main
Which of the following statement is correct as regard to centrifugal compressors?

ক
The flow of air is parallel to the axis of the compressor

খ
The static pressure of air in the impeller increases in order to provide centripetal force on the air

গ
The impeller rotates at high speeds

ঘ
The maximum efficiency is higher than multistage axial flow compressors
Ram compression in turbojet involves

ক
Reduction of speed of incoming air and conversion of part of it into pressure energy

খ
Compression of inlet air

গ
Increasing speed of incoming air

ঘ
Lost work
Which of the following fuels can be used in turbojet engines?

ক
Liquid hydrogen

খ
High speed diesel oil

গ
Kerosene

ঘ
Methyl alcohol
The maximum combustion pressure in gas turbine as compared to I.C. engine is

ক
More

খ
Less

গ
Same

ঘ
Depends on other factors
Separators in compressor installations are located

ক
Before inter-cooler

খ
After inter-cooler

গ
After receiver

ঘ
Between after-cooler and air receiver
A rocket engine uses __________ for the combustion of its fuel.

ক
Surrounding air

খ
Compressed atmospheric air

গ
Its own oxygen

ঘ
None of these
Stalling of blades in axial flow compressor is the phenomenon of

ক
Air stream blocking the passage

খ
Motion of air at sonic velocity

গ
Unsteady periodic and reversed flow

ঘ
Air stream not able to follow the blade contour
Surging is the phenomenon of

ক
Air stream blocking the passage

খ
Motion of air at sonic velocity

গ
Unsteady, periodic and reversed flow

ঘ
Air stream not able to follow the blade contour
If the flow of air through the compressor is parallel to its axis, then the compressor is

ক
Reciprocating compressor

খ
Centrifugal compressor

গ
Axial flow compressor

ঘ
Turbo compressor
The following is true for an open cycle gas turbine having exhaust heat exchanger. Atmospheric air before entering the compressor is

ক
Heated

খ
Compressed air before entering the combustion chamber is heated

গ
Bled gas from turbine is heated and readmitted for complete expansion

ঘ
Exhaust gases drive the compressor
Which is false statement about multistage compression?

ক
Power consumption per unit of air delivered is low

খ
Volumetric efficiency is high

গ
It is best suited for compression ratios around 7 : 1

ঘ
The moisture in air is condensed in the inter-cooler
The clearance volume of the air compressor is kept minimum because

ক
It allows maximum compression to be achieved

খ
It greatly affects volumetric efficiency

গ
It results in minimum work

ঘ
It permits isothermal compression
In a centrifugal compressor, an increase in speed at a given pressure ratio causes

ক
Increase in flow

খ
Decrease in flow

গ
Increase in efficiency

ঘ
Increase in flow and decrease in efficiency
More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than

ক
2 kg/cm2

খ
6 kg/cm2

গ
10 kg/cm2

ঘ
14.7 kg/cm2
The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as

ক
Compressor efficiency

খ
Volumetric efficiency

গ
Isothermal efficiency

ঘ
Mechanical efficiency
A rocket engine for the combustion of its fuel

ক
Carries its own oxygen

খ
Uses surrounding air

গ
Uses compressed atmospheric air

ঘ
Does not require oxygen