In a centrifugal compressor, the flow of air is ________ to the axis of compressor.
Parallel
Perpendicular
Inclined
None of these
Correct Answer :
B. Perpendicular
Related Questions
In a centrifugal compressor, the flow of air is ________ to the axis of compressor.
Parallel
Perpendicular
Inclined
None of these
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
Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
Backward curved blades has poor efficiency
Backward curved blades lead to stable performance
Forward curved blades has higher efficiency
Forward curved blades produce lower pressure ratio
Turbofan engine employs
One air stream
Two or more air streams
No air stream
Solid fuel firing
The process, which causes the air to enter the impeller blades of a centrifugal compressor at ________ velocity (without effecting the mass of air to flow and velocity of flow) is known as prewhirl.
Reduced
Increased
Zero
None of these
A centrifugal compressor works on the principle of
Conversion of pressure energy into kinetic energy
Conversion of kinetic energy into pressure energy
Centripetal action
Generating pressure directly
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
A compressor mostly used for supercharging of I.C. engines is
Radial flow compressor
Axial flow compressor
Roots blower
Reciprocating compressor
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 maximum combustion pressure in gas turbine as compared to I.C. engine is
More
Less
Same
Depends on other factors
Pick up the wrong statement about advantages of multistage compression
Better lubrication is possible advantages of multistage
More loss of air due to leakage past the cylinder
Mechanical balance is better
Air can be cooled perfectly in between
Maximum work is done in compressing air when the compression is
Isothermal
Adiabatic
Polytropic
None of the above
A jet engine works on the principle of conservation of
Mass
Energy
Flow
Linear momentum
For supplying intermittent small quantity of air at high pressure, following compressor is best suited
Centrifugal
Reciprocating
Axial
Screw
If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches
Isothermal
Isentropic
Adiabatic
Isochoric
The axial flow compressor is preferred in aircraft gas turbines because of
Low frontal area
Higher thrust
High pressure rise
None of these
The workdone on a compressor will be minimum if air is taken from
The atmosphere
A source at 0°C
A source of low temperature air
A source of high temperature air
The performance of air compressor at high altitudes will be ________ as compared to that at sea level.
Same
Lower
Higher
None of these
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 overall isothermal efficiency of compressor is defined as the ratio of
Isothermal h.p. to the BHP of motor
Isothermal h.p. to adiabatic h.p.
Power to drive compressor to isothermal h.p.
Work to compress air isothermally to work for actual compression
In a single acting reciprocating air compressor, without clearance, the compression of air may be
Isothermal
Polytropic
Isentropic
Any one 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
In jet engines the products of combustion after passing through the gas turbine are discharged into
Atmosphere
Back to the compressor
Discharge nozzle
Vacuum
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
The air power of the compressor is also known as
Indicated power
Brake power
Frictional power
None of these
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 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
Axial flow compressor resembles
Centrifugal pump
Reciprocating pump
Turbine
Sliding vane compressor
The velocity of air entering in a rocket is ________ as compared to an aircraft.
Zero
Less
More
Same
The efficiency of a jet engine is higher at
Low speeds
High speeds
Low altitudes
High altitudes