Volumetric efficiency of a compressor with clearance volume
Increases with increase in compression ratio
Decreases with increase in compression ratio
In not dependent upon compression ratio
May increase/decrease depending on compressor capacity
Correct Answer :
B. Decreases with increase in compression ratio
Related Questions
The most efficient method of compressing air is to compress it
Isothermally
Adiabatically
Isentropically
Isochronically
Volumetric efficiency of a compressor decreases with ________ in compression ratio.
Decrease
Increase
Remain same
Does not change
The ratio of workdone per cycle to the stroke volume of the compressor is known as
Compressor capacity
Compression ratio
Compressor efficiency
Mean effective pressure
In a jet propulsion
The propulsive matter is ejected from within the propelled body
The propulsive matter is caused to flow around the propelled body
Its functioning does not depend upon presence of air
None of the above
In open cycle turbojet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the
Thrust and range of aircraft
Efficiency of the engine
Both (A) and (B)
None of these
The pressure and temperature conditions of air at the suction of compressor are
Atmospheric
Slightly more than atmospheric
Slightly less than atmospheric
Pressure slightly less than atmospheric and temperature slightly more than atmospheric
The air power of the compressor is also known as
Indicated power
Brake power
Frictional power
None of these
The fuel consumption in gas turbines is accounted for by
Lower heating value
Higher heating value
Heating value
Higher calorific value
Inter-cooling in multistage compressors is done
To cool the air during compression
To cool the air at delivery
To enable compression in two stages
To minimise the work of compression
The blades of gas turbine are made of
High nickel alloy
Stainless steel
Carbon steel
High alloy steel
The volumetric efficiency of compressor with increase in compression ratio will
Increase
Decrease
Remain same
May increase or decrease depending on clearance volume
In which case the air-fuel ratio is likely to be maximum?
Gas turbine
4-stroke petrol engine
4-stroke diesel engine
Multi cylinder engine
Which of the following statement is correct?
The reciprocating compressors are best suited for high pressure and low volume capacity
The effect of clearance volume on power consumption is negligible for the same volume of discharge
Both (A) and (B)
None of these
In gas turbines, high thermal efficiency is obtained in
Closed cycle
Open cycle
Both of the above
Closed/open depending on other considerations
For minimum work in multistage compression, assuming same index of compression in all stages
Work done in first stage should be more
Work done in subsequent stages should increase
Work done in subsequent stages should decrease
Work done in all stages should be equal
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)
p₂ = p₁ × p₃
p₂ = p₁/p₃
p₂ = p₁ × p₂
p₂ = p₃/p₁
Losses in a centrifugal compressor are due to
Inlet losses
Impeller channel losses
Diffuser losses
All of the above
The volumetric efficiency for reciprocating air compressors is about
10 to 40 %
40 to 60 %
60 to 70 %
70 to 90 %
Inter-cooling in gas turbine results in
Increase in net output but decrease in thermal efficiency
Increase in thermal efficiency but decrease in net output
Increase in both thermal efficiency and net output
Decrease in both thermal efficiency and net output
Which of the following fuels can be used in turbojet engines?
Liquid hydrogen
High speed diesel oil
Kerosene
Methyl alcohol
Which of the following statement is correct relating to rocket engines?
The combustion chamber in a rocket engine is directly analogous to the reservoir of a supersonic wind tunnel
The stagnation conditions exist at the combustion chamber
The exit velocities of exhaust gases are much higher than those in jet engine
All of the above
The volumetric efficiency of a compressor falls roughly as follows for every 5°C increase in atmospheric temperature
0.1 %
0.5 %
1 %
5 %
If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix I and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity
Vi = Vo
Vt > Vo
U < Vo
V = Uo
The compressed air may be used
In gas turbine plants
For operating pneumatic drills
In starting and supercharging of I.C. engines
All of the above
What will be the volume of air at 327°C if its volume at 27°C is 1.5 m³/ mt?
3 m³/ mt.
1.5 m³/ mt.
18 m³/ mt.
6 m³/ mt.
A simple turbojet engine is basically
A propeller system
Gas turbine engine equipped with a propulsive nozzle and diffuse
Chemical rocket engine
Ramjet engine
The performance of air compressor at high altitudes will be ________ as compared to that at sea level.
Same
Lower
Higher
None of these
In turbo fan engine, the jet velocity as compared to turbojet engine is
Less
More
Same
May be less or more depending upon speed
Rotary compressor is best suited for
Large quantity of air at high pressure
Small quantity of air at high pressure
Small quantity of air at low pressure
Large quantity of air at low pressure
The maximum compression ratio in an actual single stage axial flow compressor is of the order of
1 : 1.2
1 : 2
1 : 5
1 : 10