The thermodynamic efficiency of rotary compressor is based on
Isothermal compression
Adiabatic compression
Isentropic compression
Polytropic compression
Correct Answer :
B. Adiabatic compression
Related Questions
When air is to be compressed at a high pressure, then it is advantageous to use
Single stage compression
Multistage compression without intercooling
Multistage compression with intercooling
None of these
A rocket works with maximum overall efficiency when air craft velocity is equal to the
Jet velocity
Twice the jet velocity
Half the jet velocity
Average of the jet velocity
If the flow of air through the compressor is perpendicular to its axis, then it is a
Reciprocating compressor
Centrifugal compressor
Axial flow compressor
Turbo compressor
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
Gas turbines use following type of air compressor
Centrifugal type
Reciprocating type
Lobe type
Axial flow type
The type of rotary compressor used in aeroplanes, is of
Centrifugal type
Axial flow type
Radial flow type
None of these
Mining industry usually employs following motive power
A.C. electric motor
Compressed air
Petrol engine
Diesel engine
Pick up the wrong statement
Centrifugal compressors deliver practically constant pressure over a considerable range of capacities
Axial flow compressors have a substantially constant delivery at variable pressures
Centrifugal compressors have a wider stable operating range than axial flow compressors
Axial flow compressors are bigger in diameter compared to centrifugal type
Work ratio of a gas turbine plant is ratio of
Net work output and work done by turbine
Net work output and heat supplied
Work done by turbine and heat supplied
Work done by turbine and net work output
When the outlet angle from the rotor of a centrifugal compressor is more than 90°, then the blades are said to be
Forward curved
Backward curved
Radial
None of these
The air power of the compressor is also known as
Indicated power
Brake power
Frictional power
None of these
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
The air is delivered ________ in one revolution in case of a three lobbed rotor.
Two times
Three times
Four times
Six times
In gas turbines, high thermal efficiency is obtained in
Closed cycle
Open cycle
Both of the above
Closed/open depending on other considerations
Clearance volume in actual reciprocating compressors is essential
To accommodate Valves in the cylinder head
To provide cushioning effect
To attain high volumetric efficiency
To provide cushioning effect and also to avoid mechanical bang of piston with cylinder head
Separators are generally used in air compressor installations
Before the intercooler
After the intercooler
Between the aftercooler and receiver
Before first stage suction
A machine used to raise the pressure of air is called
Gas turbine
I.C engine
Compressor
Air motor
The degree of reaction is usually kept ________ for all types of axial flow compressors.
0.2
0.3
0.4
0.5
The combustion efficiency of a gas turbine using perfect combustion chamber is of the order of
75 %
85 %
90 %
99 %
Euler's equation can be used for
Radial flow compressors
Axial flow compressors
Pumps
All of these
Propulsive efficiency is defined as ratio of
Thrust power and fuel energy
Engine output and propulsive power
Propulsive power and fuel input
Thrust power and propulsive power
For an irreversible gas turbine cycle, the efficiency and work ratio both depend on
Pressure ratio alone
Maximum cycle temperature alone
Minimum cycle temperature alone
Both pressure ratio and maximum cycle temperature
In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into
Atmosphere
Vacuum
Discharge nozzle
Back to the compressor
The pressure ratio of an ideal vaned compressor with increase in mass flow rate
Increases
Decreases
Remain constant
First decreases and then increases
Aeroplanes employ following type of compressor
Radial flow
Axial flow
Centrifugal
None of the above
The compression ratio for the compressor is always __________ unity.
Equal to
Less than
More than
None of these
In n₁ and n₂ are the indices of compression for the first and second stage of compression, then the ratio of workdone on the first and second stages (W₁/W₂) with perfect intercooling is given by
W₁/W₂ = n₂(n₁ - 1)/n₁(n₂ - 1)
W₁/W₂ = n₁(n₂ - 1)/n₂(n₁ - 1)
W₁/W₂ = n₁/n₂
W₁/W₂ = n₂/n₁
In a centrifugal compressor, the flow of air is ________ to the axis of compressor.
Parallel
Perpendicular
Inclined
None of these
The compressor capacity is defined as 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
The weight per horse power ratio for gas in Turbine as compared to I.C. engine and steam turbine is
Same
Higher
Lower
None of these