The ideal efficiency of simple gas turbine cycle depends on
Pressure ratio
Maximum cycle temperature
Minimum cycle temperature
All of the above
Correct Answer :
A. Pressure ratio
Related Questions
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
The efficiency of roots blower ________ with the increase in pressure ratio.
Decreases
Increases
Does not change
None of these
The degree of reaction is usually kept ________ for all types of axial flow compressors.
0.2
0.3
0.4
0.5
The volumetric efficiency of compressor with increase in compression ratio will
Increase
Decrease
Remain same
May increase or decrease depending on clearance volume
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
Turbofan engine employs
One air stream
Two or more air streams
No air stream
Solid fuel firing
For supplying intermittent small quantity of air at high pressure, following compressor is best suited
Centrifugal
Reciprocating
Axial
Screw
Temperature of gases at end of compression as compared to exhaust gases in a gas turbine is
Higher
Lower
Equal
Cant be compared
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 jet engines the products of combustion after passing through the gas turbine are discharged into
Atmosphere
Back to the compressor
Discharge nozzle
Vacuum
Pick up the correct statement
Gas turbine uses low air-fuel ratio to economise on fuel
Gas turbine uses high air-fuel ratio to reduce outgoing temperature
Gas turbine uses low air-fuel ratio to develop the high thrust required
All of the above
Axial flow compressor resembles
Centrifugal pump
Reciprocating pump
Turbine
Sliding vane compressor
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
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 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
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
The ratio of specific weight/h.p. of gas turbine and I.C engines may be typically of the order of
1 : 1
2 : 1
4 : 1
1 : 6
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 capacity of a compressor is expressed in
kg/m²
kg/m³
m³/min
m³/kg
The ratio of the increase in pressure in rotor blades to total increase in pressure in the stage is called
Pressure ratio
Pressure coefficient
Degree of reaction
Slip factor
The volumetric efficiency of a compressor falls roughly as follows for every 5°C increase in atmospheric temperature
0.1 %
0.5 %
1 %
5 %
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.
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 efficiency and work ratio of a gas turbine plant can be increased by
Adding heat exchanger
Injecting water in/around combustion chamber
Reheating the air after partial expansion in the turbine
All of the above
Pick up the correct statement
Closed cycle gas turbine is an I.C engine
Gas turbine uses same working fluid over and over again
Ideal efficiency of closed cycle gas turbine plant is more than Carnot cycle efficiency
Thrust in turbojet is produced by nozzle exit gases.
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 working fluid in a turbine is
In two phases
In three phases
In a single phase
In the form of air and water mixture
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
The effective power of gas turbines is increased by adding the following in compressor
Ammonia and water vapour
Carbon dioxide
Nitrogen
Hydrogen
Gas turbine blades are given a rake
Equal to zero
In the direction of motion of blades
Opposite to the direction of motion of blades
Depending on the velocity