A large clearance volume in a reciprocating compressor results in
Reduced volume flow rate
Increased volume flow rate
Lower suction pressure
Lower delivery pressure
Correct Answer :
A. Reduced volume flow rate
Related Questions
An air compressor may be controlled by
Throttle control
Clearance control
Blow off control
Any one of the above
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
In jet engines the products of combustion after passing through the gas turbine are discharged into
Atmosphere
Back to the compressor
Discharge nozzle
Vacuum
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
The output of a gas turbine is 300 KW and its efficiency is 20 percent, the heat supplied is
6000 KW
15 KW
600 KW
150 KW
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
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
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 the axial flow gas turbine, the work ratio is the ratio of
Compressor work and turbine work
Output and input
Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet
Actual compressor work and theoretical compressor work
The clearance volume of the air compressor is kept minimum because
It allows maximum compression to be achieved
It greatly affects volumetric efficiency
It results in minimum work
It permits isothermal compression
Which is false statement about advantages of multistage compressor in comparison to single stage compressor?
Less power requirement
Better mechanical balance
Less loss of air due to leakage past the cylinder
Lower volumetric efficiency
The compression ratio in a gas turbine is of the order of
3.5 : 1
5 : 1
8 : 1
12 : 1
In a single acting reciprocating air compressor, without clearance, the compression of air may be
Isothermal
Polytropic
Isentropic
Any one of these
Mechanical efficiency of gas turbines as compared to I.C engines is
Higher
Lower
Same
None of the above
The overall efficiency of the compressed air system is the
Ratio of shaft output of the air motor to the shaft input to the compressor
Ratio of shaft input to the compressor to the shaft output of air motor
Product of shaft output of air motor and shaft input to the compressor
None of the above
The thermal efficiency of a simple gas turbine for a given turbine inlet temperature with increase in pressure ratio
Increases
Decreases
First increases and then decreases
First decreases and then increases
In jet propulsion power unit, the inlet duct of diverging shape is used in order to
Collect more air
Convert kinetic energy of air into pressure energy
Provide robust structure
Beautify the shape
If the flow of air through the compressor is parallel to its axis, then the compressor is
Reciprocating compressor
Centrifugal compressor
Axial flow compressor
Turbo compressor
Work ratio of a gas turbine may be improved by
Decreasing the compression work
Increasing the compression work
Increasing the turbine work
Both (A) and (C) above
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
A turboprop is preferred to turbojet because
It has high propulsive efficiency at high speeds
It can fly at supersonic speeds
It can fly at high elevations
It has high power for take off
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
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
More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than
2 kg/cm²
6 kg/cm²
10 kg/cm²
14.7 kg/cm²
Inter cooling in compressors
Cools the delivered air
Results in saving of power in compressing a given volume to given pressure
Is the standard practice for big compressors
Enables compression in two stages
In the cross compounding of the gas turbine plant
H.P. compressor is connected to H.P. turbine and L.P. compressor to L.P. turbine
H.P. compressor is connected to L.P. turbine and L.P. compressor is connected to H.P. turbine
Both the arrangements can be employed
All are connected in series
The most efficient method of compressing air is to compress it
Isothermally
Adiabatically
Isentropically
Isochronically
There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would
Remain same
Decrease
Increase
None of the above
Aeroplanes employ following type of compressor
Radial flow
Axial flow
Centrifugal
None of the above
The overall isothermal efficiency of the compressor is defined as the ratio of
Work required to compress the air isothermally to the actual work required to compress the air for the same pressure ratio
Isothermal power to the shaft power or B.P. of the motor or engine required to drive the compressor
Volume of free air delivery per stroke to the swept volume of the piston
Isentropic power to the power required to drive the compressor