Which is false statement about air receivers?
These are used to dampen pulsations
These act as reservoir to take care of sudden demands
These increase compressor efficiency
These knock out some oil and moisture
Correct Answer :
C. These increase compressor efficiency
Related Questions
For perfect intercooling in a two stage compressor
p₂/p₁ = p₃/p₂
p₁/p₃ = p₂/p₁
p₁ = p₃
p₁ = p₂ p₃
Isothermal compression efficiency, even when running at high speed, can be approached by using
Multistage compression
Cold water spray
Both (A) and (B) above
Fully insulating the cylinder
In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of
Vacuum
Atmospheric air
Compressed air
Oxygen alone
Reheating in a gas turbine
Increases the thermal efficiency
Increases the compressor work
Increases the turbine work
Decreases the thermal efficiency
The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the
Adiabatic temperature drop in the stage
Total temperature drop
Total temperature drop in the stage
Total adiabatic temperature drop
Free air is the air at
Atmospheric conditions at any specific location
20°C and 1 kg/cm² and relative humidity of 36%
0°C and standard atmospheric conditions
15°C and 1 kg/cm²
The fuel consumption in gas turbines is accounted for by
Lower heating value
Higher heating value
Heating value
Higher calorific value
Which is false statement about multistage compression?
Power consumption per unit of air delivered is low
Volumetric efficiency is high
It is best suited for compression ratios around 7:1
The moisture in air is condensed in the intercooler
The ratio of work done per cycle to the swept volume in case of compressor is called
Compression index
Compression ratio
Compressor efficiency
Mean effective pressure
A machine used to raise the pressure of air is called
Gas turbine
I.C engine
Compressor
Air motor
Maximum temperature in a gas turbine is of the order of
700°C
2000°C
1500°C
1000°C
During base load operation, the best method of controlling compressor is
Start-stop motor
Constant speed unloader
Relief valve
Variable speed
Volumetric efficiency of a compressor decreases with ________ in compression ratio.
Decrease
Increase
Remain same
Does not change
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
Standard air is the air at ________ and relative humidity of 36 percent.
0.1 bar and 20°C
1 bar and 20°C
0.1 bar and 40°C
1 bar and 40°C
Compression efficiency is compared against
Ideal compression
Adiabatic compression
Isentropic compression
Isothermal compression
The blades of gas turbine are made of
High nickel alloy
Stainless steel
Carbon steel
High alloy steel
An air compressor may be controlled by
Throttle control
Clearance control
Blow off control
Any one of the above
The type of rotary compressor used in aeroplanes, is of
Centrifugal type
Axial flow type
Radial flow type
None of these
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
Work factor
Slip factor
Degree of reaction
Pressure coefficient
A large clearance volume in a reciprocating compressor results in
Reduced volume flow rate
Increased volume flow rate
Lower suction pressure
Lower delivery pressure
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
In a single acting reciprocating air compressor, without clearance, the compression of air may be
Isothermal
Polytropic
Isentropic
Any one of these
Stalling of blades in axial flow compressor is the phenomenon of
Air stream blocking the passage
Motion of air at sonic velocity
Unsteady periodic and reversed flow
Air stream not able to follow the blade contour
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
The maximum temperature in a gas turbine is
200°C
500°C
700°C
1000°C
Which of the following plants is smallest and lightest for generating a given amount of power?
Gas turbine plant
Petrol engine
Diesel engine
Solar plant
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 following property is most important for material used for gas turbine blade
Toughness
Fatigue
Creep
Corrosion resistance