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
Correct Answer :
B. Work ratio
Related Questions
The type of rotary compressor used in gas turbines, is of
Centrifugal type
Axial flow type
Radial flow type
None of these
Reheating in multistage expansion gas turbine results in
High thermal efficiency
Reduction in compressor work
Decrease of heat loss in exhaust
Maximum work output
The maximum temperature in a gas turbine is
200°C
500°C
700°C
1000°C
The combustion efficiency of a gas turbine using perfect combustion chamber is of the order of
75 %
85 %
90 %
99 %
The compressor capacity with decrease in suction temperature
Increases
Decreases
Remain unaffected
May increase or decrease depending on compressor capacity
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
Gas turbine cycle with regenerator
Increases thermal efficiency
Allows high compression ratio
Decreases heat loss is exhaust
Allows operation at very high altitudes
The mass of gas turbine per kW developed is about ________ as that of an I.C. engine.
Same
One-half
One fourth
One sixth
In jet engines, paraffin is usually used as the fuel because of its
High calorific value
Ease of atomisation
Low freezing point
Both (A) and (C) above
To avoid moisture troubles, the branch connections from compressed air lines should be taken from
Top side of main
Bottom side of main
Left side of main
Right side of main
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
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
Inter-cooling in multistage compressors is done
To cool the air during compression
To cool the air at delivery
To enable compression in two stages
To minimise the work of compression
The overall efficiency of the compressed air system is the
Ratio of shaft output of the air motor to the shaft input to the compressor
Ratio of shaft input to the compressor to the shaft output of air motor
Product of shaft output of air motor and shaft input to the compressor
None of the above
In the axial flow gas turbine, the work ratio is the ratio of
Compressor work and turbine work
Output and input
Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet
Actual compressor work and theoretical compressor work
In a compressor, free air delivered is the actual volume delivered at the stated pressure reduced to
N.T.P. conditions
Intake temperature and pressure conditions
0°C and 1 kg/cm²
20°C and 1 kg/cm²
In a jet engine, the air-fuel ratio is
30 : 1
40 : 1
50 : 1
60 : 1
The capacity of a compressor is expressed in
kg/m²
kg/m³
m³/min
m³/kg
The degree of reaction in an axial flow compressor is defined as the ratio of static enthalpy rise in the
Rotor to static enthalpy rise in the stator
Stator to static enthalpy rise in the rotor
Rotor to static enthalpy rise in the stage
Stator to static enthalpy rise in the stage
Efficiency of gas turbine is increased by
Reheating
Inter cooling
Adding a regenerator
All of the above
Axial flow compressor has the following advantage over centrifugal compressor
Larger air handling ability per unit frontal area
Higher pressure ratio per stage
Aerofoil blades are used
Higher average velocities
The compressor performance at higher altitude compared to sea level will be
Same
Higher
Lower
Dependent on other factors
If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches
Isothermal
Isentropic
Adiabatic
Isochoric
A closed cycle gas turbine works on
Carnot cycle
Rankine cycle
Ericsson cycle
Joule cycle
The ratio of isentropic work to Eulers work is known as
Compressor efficiency
Isentropic efficiency
Euler's efficiency
Pressure coefficient
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
A simple turbojet engine is basically
A propeller system
Gas turbine engine equipped with a propulsive nozzle and diffuse
Chemical rocket engine
Ramjet engine
Pressure ratio in gas turbines is the ratio of
Compressor pressure ratio
Highest pressure to exhaust pressure
Inlet pressure to exhaust pressure
Pressures across the turbine
The net work input required for compressor with increase in clearance volume
Increases
Decreases
Remains same
Increases/decreases depending on compressor capacity
The capacity of a compressor is 5 m /min refers to
Standard air
Free air
Compressed air
Compressed air at delivery pressure