The closed cycle in gas turbines
Provides greater flexibility
Provides lesser flexibility
In never used
Is used when gas is to be burnt
Correct Answer :
A. Provides greater flexibility
Related Questions
The ideal efficiency of simple gas turbine cycle depends on
Pressure ratio
Maximum cycle temperature
Minimum cycle temperature
All of the above
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
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 capacity of a compressor is 5 m /min refers to
Standard air
Free air
Compressed air
Compressed air at delivery pressure
In a double acting compressor, the air is compressed
In one cylinder
In two cylinders
In a single cylinder on both sides of the piston
In two cylinders on both sides of the piston
Phenomenon of choking in compressor means
No flow of air
Fixed mass flow rate regardless of pressure ratio
Reducing mass flow rate with increase in pressure ratio
Increased inclination of chord with air steam
The criterion of the thermodynamic efficiency for rotary compressor is
Isentropic compression
Isothermal compression
Polytropic compression
None of the above
The closed cycle in gas turbines
Provides greater flexibility
Provides lesser flexibility
In never used
Is used when gas is to be burnt
Losses in a centrifugal compressor are due to
Inlet losses
Impeller channel losses
Diffuser losses
All of the above
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
The capacity of a compressor is expressed in
kg/m²
kg/m³
m³/min
m³/kg
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
The ratio of isentropic work to Euler work is known as
Pressure coefficient
Work coefficient
Polytropic reaction
Slip factor
The maximum delivery pressure in a rotary air compressor is
10 bar
20 bar
30 bar
50 bar
A closed cycle gas turbine gives ________ efficiency as compared to an open cycle gas turbine.
Same
Lower
Higher
None of these
Ratio of indicated h.p. to shaft h.p. in known as
Compressor efficiency
Isothermal efficiency
Volumetric efficiency
Mechanical efficiency
The air is delivered ________ in one revolution in case of a three lobbed rotor.
Two times
Three times
Four times
Six times
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
The thrust of a jet propulsion power unit can be increased by
Injecting water into the compressor
Burning fuel after gas turbine
Injecting ammonia into the combustion chamber
All of the above
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
Cylinder clearance in a compressor should be
As large as possible
As small as possible
About 50% of swept volume
About 100% of swept volume
The capacity of compressor will be highest when its intake temperature is
Lowest
Highest
Anything
Atmospheric
Rotary compressors are used for delivering
Small quantities of air at high pressures
Large quantities of air at high pressures
Small quantities of air at low pressures
Large quantities of air at low pressures
The compressor capacity with decrease in suction temperature
Increases
Decreases
Remain unaffected
May increase or decrease depending on compressor capacity
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
Gas turbines use following type of air compressor
Centrifugal type
Reciprocating type
Lobe type
Axial flow type
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
The compressor efficiency is the
Isothermal H.P/indicated H.R
Isothermal H.P./shaft H.R
Total output/air input
Compression work/motor input
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 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