The compression ratio for the compressor is always __________ unity.
Equal to
Less than
More than
None of these
Correct Answer :
C. More than
Related Questions
Compression efficiency is compared against
Ideal compression
Adiabatic compression
Isentropic compression
Isothermal compression
The area of actual indicator diagram on an air compressor as compared to area of ideal indicator diagram is
Less
More
Same
More/less depending on compressor capacity
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
Water is injected in gas turbine cycle to
Control temperature
Control output of turbine
Control fire hazards
Increase efficiency
The propulsive power of the rocket is (where v₁ = Jet velocity, and v₂ = Aircraft velocity)
(v₁² -v₂²)/2g
(v₁ - v₂)²/2g
(v₁² -v₂²)/g
(v₁ - v₂)²/g
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
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
Euler's equation is applicable for
Centrifugal compressor
Axial compressor
Pumps
All of the above
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
If the clearance ratio for a reciprocating air compressor is 'K', then its volumetric efficiency is given by
1 - k + k (p₁/p₂)1/n
1 + k - k (p₂/p₁)1/n
1 - k + k (p₁/p₂) n- 1/n
1 + k - k (p₂/p₁) n-1/n
The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as
Compressor efficiency
Volumetric efficiency
Isothermal efficiency
Mechanical efficiency
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
In the aircraft propellers
The propulsive matter is caused to flow around the propelled body
Propulsive matter is ejected from within the propelled body
Its functioning does not depend on presence of air
All of the above
The volumetric efficiency of compressor with increase in compression ratio will
Increase
Decrease
Remain same
May increase or decrease depending on clearance volume
Aeroplanes employ following type of compressor
Radial flow
Axial flow
Centrifugal
None of the above
Maximum work is done in compressing air when the compression is
Isothermal
Adiabatic
Polytropic
None of the above
Efficiency of gas turbine is increased by
Reheating
Inter cooling
Adding a regenerator
All of the above
Reheating in a gas turbine
Increases the thermal efficiency
Increases the compressor work
Increases the turbine work
Decreases the thermal efficiency
In a closed cycle gas turbine, the air is compressed
Isothermally
Polytropically
Isentropically
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
The volume of air delivered by the compressor is called
Free air delivery
Compressor capacity
Swept volume
None of these
Gas turbines for power generation are normally used
To supply base load requirements
To supply peak load requirements
To enable start thermal power plant
In emergency
The compression ratio for the compressor is always __________ unity.
Equal to
Less than
More than
None of these
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
Adiabatic compression is one in which
Temperature during compression remains constant
No heat leaves or enters the compressor cylinder during compression
Temperature rise follows a linear relationship
Work done is maximum
The ratio of isentropic work to Euler work is known as
Pressure coefficient
Work coefficient
Polytropic reaction
Slip factor
The air-fuel ratio in gas turbines is of the order of
7 : 1
15 : 1
30 : 1
50 : 1.
The maximum temperature in a gas turbine is
200°C
500°C
700°C
1000°C
A rocket engine for the combustion of its fuel
Carries its own oxygen
Uses surrounding air
Uses compressed atmospheric air
Does not require oxygen
Ratio of indicated H.P. and brake H.P. is known as
Mechanical efficiency
Volumetric efficiency
Isothermal efficiency
Adiabatic efficiency