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
Correct Answer :
B. Centrifugal compressor
Related Questions
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
In a single acting reciprocating air compressor, without clearance, the compression of air may be
Isothermal
Polytropic
Isentropic
Any one of these
The ratio of work done per cycle to the swept volume in case of compressor is called
Compression index
Compression ratio
Compressor efficiency
Mean effective pressure
In a single stage, single acting reciprocating air compressor without clearance volume, the workdone is maximum during
Isothermal compression
Isentropic compression
Polytropic compression
None of these
An aftercooler is used to
Remove impurities from air
Reduce volume of air
Cause moisture and oil vapour to drop out
Cool the air
The specific output per kg mass flow rate of a gas turbine (having fixed efficiencies of compressor and turbine and fixed higher and lower temperature) with increase in pressure ratio will
Increase first at fast rate and then slow
Increase first at slow rate and then fast
Decrease continuously
First increase, reach maximum and then decrease
Compression efficiency is compared against
Ideal compression
Adiabatic compression
Isentropic compression
Isothermal compression
Actual compression curve is
Same as isothermal
Same as adiabatic
Better than isothermal and adiabatic
In between isothermal and adiabatic
For speed above 3000 km/hour, it is more advantageous to use
Turbojet engine
Ramjet engine
Propellers
Rockets
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
A large clearance volume in a reciprocating compressor results in
Reduced volume flow rate
Increased volume flow rate
Lower suction pressure
Lower delivery pressure
Volumetric efficiency of a compressor with clearance volume
Increases with increase in compression ratio
Decreases with increase in compression ratio
In not dependent upon compression ratio
May increase/decrease depending on compressor capacity
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
The air-fuel ratio in gas turbines is of the order of
7 : 1
15 : 1
30 : 1
50 : 1.
When the temperature of air leaving the intercooler, in a two stage compression with intercooler, is ________ the original atmospheric air temperature, then the intercooling is known as perfect or complete intercooling.
Equal to
Less than
More than
None of these
A simple turbojet engine is basically
A propeller system
Gas turbine engine equipped with a propulsive nozzle and diffuse
Chemical rocket engine
Ramjet engine
Ratio of indicated H.P. and brake H.P. is known as
Mechanical efficiency
Volumetric efficiency
Isothermal efficiency
Adiabatic efficiency
The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation
0.1 %
0.5 %
1.0 %
5 %
Reheating in a gas turbine
Increases the thermal efficiency
Increases the compressor work
Increases the turbine work
Decreases the thermal efficiency
The ratio of the net work obtained from the gas turbine plant to the turbine work is known as
Compression ratio
Work ratio
Pressure ratio
None of these
The maximum compression ratio in an actual single stage axial flow compressor is of the order of
1 : 1.2
1 : 2
1 : 5
1 : 10
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
The work ratio of a gas turbine plant is defined as the ratio of
Net work output and heat supplied
Net work output and work done by turbine
Actual heat drop and isentropic heat drop
Net work output and isentropic heat drop
Which of the following statement is wrong?
In a two stage reciprocating air compressor with complete intercooling, maximum work is saved.
The minimum work required for a two stage reciprocating air compressor is double the work required for each stage.
The ratio of the volume of free air delivery per stroke to the swept volume of the piston is called volumetric efficiency.
None of the above
A jet engine works on the principle of conservation of
Mass
Energy
Flow
Linear momentum
The degree of reaction is usually kept ________ for all types of axial flow compressors.
0.2
0.3
0.4
0.5
If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix I and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity
Vi = Vo
Vt > Vo
U < Vo
V = Uo
Reciprocating air compressor is best suited for
Large quantity of air at high pressure
Small quantity of air at high pressure
Small quantity of air at low pressure
Large quantity of air at low pressure
Only rocket engines can be propelled to space because
They can generate very high thrust
They have high propulsion efficiency
These engines can work on several fuels
They are not air breathing engines
Volumetric efficiency is
The ratio of stroke volume to clearance volume
The ratio of the air actually delivered to the amount of piston displacement
Reciprocal of compression ratio
Index of compressor performance