The capacity of a compressor is 5 m /min refers to
Standard air
Free air
Compressed air
Compressed air at delivery pressure
Correct Answer :
B. Free air
Related Questions
The mean effective pressure of the compressor is the
Actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions
Volume of air delivered by the compressor
Volume of air sucked by the compressor during its suction stroke
None of the above
Choose the correct statement
Gas turbine requires lot of cooling water
Gas turbine is capable of rapid start up and loading
Gas turbines has flat efficiency at part loads
Gas turbines have high standby losses and require lot of maintenance
Intercooling in gas turbines
Decreases net output but increases thermal efficiency
Increases net output but decreases thermal efficiency
Decreases net output and thermal efficiency both
Increases net output and thermal efficiency both
The most efficient method of compressing air is to compress it
Isothermally
Adiabatically
Isentropically
Isochronically
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
To avoid moisture troubles, the compressed air main line should
Rise gradually towards the point of use
Drop gradually towards the point of use
Be laid vertically
Be laid exactly horizontally
Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
Backward curved blades has poor efficiency
Backward curved blades lead to stable performance
Forward curved blades has higher efficiency
Forward curved blades produce lower pressure ratio
The ratio of the indicated power to the shaft power or brake power of the motor or engine required to drive the compressor, is called
Compressor efficiency
Volumetric efficiency
Isothermal efficiency
Mechanical efficiency
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 maximum temperature in a gas turbine is
200°C
500°C
700°C
1000°C
Volumetric efficiency of a compressor decreases with ________ in compression ratio.
Decrease
Increase
Remain same
Does not change
Separators are generally used in air compressor installations
Before the intercooler
After the intercooler
Between the aftercooler and receiver
Before first stage suction
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
The maximum combustion pressure in gas turbine as compared to I.C. engine is
More
Less
Same
Depends on other factors
The reason for volumetric efficiency of reciprocating compressor being less than 100 percent is
Pressure drop across the valves
Superheating in compressor
Clearance volume and leakages
All of these
Mechanical efficiency of gas turbines as compared to I.C engines is
Higher
Lower
Same
None of the above
In a four stage compressor, if the pressure at the first and third stage is 1 bar and 16 bar, then the delivery pressure at the fourth stage will be
1 bar
16 bar
64 bar
256 bar
Maximum temperature in a gas turbine is of the order of
700°C
2000°C
1500°C
1000°C
An ideal air compressor cycle without clearance on PV diagram can be represented by following processes
One adiabatic, two isobaric, and one constant volume
Two adiabatic and two isobaric
Two adiabatic, one isobaric and one constant volume
One adiabatic, one isobaric and two constant volumes
Air-fuel ratio in a jet engine will be of the order of
10 : 1
15 : 1
20 : 1
60 : 1
The work ratio of simple gas turbine cycle depends on
Pressure ratio
Maximum cycle temperature
Minimum cycle temperature
All of the above
Efficiency of gas turbine is increased by
Reheating
Inter cooling
Adding a regenerator
All of the above
In a high pressure compressor, the delivery pressure is
1 to 5 bar
5 to 8 bar
8 to 10 bar
10 to 15 bar
In a centrifugal compressor, the highest Mach number leading to shock wave in the fluid flow occurs at
Diffuser inlet radius
Diffuser outlet radius
Impeller inlet radius
Impeller outlet radius
The volume of air delivered in a medium capacity air compressor per unit time is
0.1 to 1.2 m³/s
0.15 to 5 m³/s
Above 5 m³/s
None of these
Pick up the wrong statement
Large gas turbines employ axial flow compressors
Axial flow compressors are more stable than centrifugal type compressors but not as efficient
Axial flow compressors have high capacity and efficiency
Axial flow compressors have instability region of operation
The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called
Slip factor
Velocity factor
Velocity coefficient
None of the above
The compressor capacity with decrease in suction temperature
Increases
Decreases
Remain unaffected
May increase or decrease depending on compressor capacity
Ratio of compression is the ratio of
Gauge discharge pressure to the gauge intake pressure
Absolute discharge pressure to the absolute intake pressure
Pressures at discharge and suction corresponding to same temperature
Stroke volume and clearance volume
The closed cycle in gas turbines
Provides greater flexibility
Provides lesser flexibility
In never used
Is used when gas is to be burnt