Free air is the air at
Atmospheric conditions at any specific location
20°C and 1 kg/cm² and relative humidity of 36%
0°C and standard atmospheric conditions
15°C and 1 kg/cm²
Correct Answer :
A. Atmospheric conditions at any specific location
Related Questions
The volumetric efficiency of a compressor falls roughly as follows for every 5°C increase in atmospheric temperature
0.1 %
0.5 %
1 %
5 %
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
A large clearance volume in a reciprocating compressor results in
Reduced volume flow rate
Increased volume flow rate
Lower suction pressure
Lower delivery pressure
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
Standard air is the air at
Atmospheric conditions at any specific location
20°C and 1 kg/cm² and relative humidity 36%
0°C and standard atmospheric conditions
15°C and 1 kg/cm²
If p₁, is the pressure of air entering the L.P. cylinder and p₂ is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D₁ = Dia. of L.P. cylinder, and D₂ = Dia. of H.P. cylinder)
D₁/D₂ = p₁ p₂
D₁/D₂ = p₁/p₂
D₁/D₂ = p₂/p₁
None of these
The mass of gas turbine per kW developed is about ________ as that of an I.C. engine.
Same
One-half
One fourth
One sixth
The axial flow compressor is preferred in aircraft gas turbines because of
Low frontal area
Higher thrust
High pressure rise
None of these
A jet engine works on the principle of conservation of
Mass
Energy
Flow
Linear momentum
The maximum combustion pressure in gas turbine as compared to I.C. engine is
More
Less
Same
Depends on other factors
In turbo fan engine, the jet velocity as compared to turbojet engine is
Less
More
Same
May be less or more depending upon speed
Turbofan engine employs
One air stream
Two or more air streams
No air stream
Solid fuel firing
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
The efficiency of a jet engine is higher at
Low speeds
High speeds
Low altitudes
High altitudes
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
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
Which of the following statement is correct as regard to centrifugal compressors?
The flow of air is parallel to the axis of the compressor
The static pressure of air in the impeller increases in order to provide centripetal force on the air
The impeller rotates at high speeds
The maximum efficiency is higher than multistage axial flow compressors
Atmospheric pressure is 1.03 kg/cm and vapour pressure is 0.03 kg/cm. The air pressure will be
1.03 kg/cm²
1.06 kg/cm²
1.00 kg/cm²
0.53 kg/cm²
Surging is the phenomenon of
Air stream blocking the passage
Motion of air at sonic velocity
Unsteady, periodic and reversed flow
Air stream not able to follow the blade contour
Air-fuel ratio in a jet engine will be of the order of
10 : 1
15 : 1
20 : 1
60 : 1
Pick up the wrong statement
Centrifugal compressors deliver practically constant pressure over a considerable range of capacities
Axial flow compressors have a substantially constant delivery at variable pressures
Centrifugal compressors have a wider stable operating range than axial flow compressors
Axial flow compressors are bigger in diameter compared to centrifugal type
Reheating in a gas turbine
Increases the thermal efficiency
Increases the compressor work
Increases the turbine work
Decreases the thermal efficiency
The net work input required for compressor with increase in clearance volume
Increases
Decreases
Remains same
Increases/decreases depending on compressor capacity
The thermal efficiency of a gas turbine as compared to a diesel plant is
Same
More
Less
Depends on other factors
The velocity of air entering in a rocket is ________ as compared to an aircraft.
Zero
Less
More
Same
The pressure and temperature conditions of air at the suction of compressor are
Atmospheric
Slightly more than atmospheric
Slightly less than atmospheric
Pressure slightly less than atmospheric and temperature slightly more than atmospheric
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 compressor mostly used for supercharging of I.C. engines is
Radial flow compressor
Axial flow compressor
Roots blower
Reciprocating compressor
The maximum temperature in a gas turbine is
200°C
500°C
700°C
1000°C
Axial flow compressor resembles
Centrifugal pump
Reciprocating pump
Turbine
Sliding vane compressor