The thermal efficiency of a gas turbine as compared to a diesel plant is
Same
More
Less
Depends on other factors
Correct Answer :
C. Less
Related Questions
Mining industry usually employs following motive power
A.C. electric motor
Compressed air
Petrol engine
Diesel engine
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
Pick up wrong statement. Surging phenomenon in centrifugal compressor depends on
Mass flow rate
Pressure ratio
Change in load
Stagnation pressure at the outlet
Mechanical efficiency of gas turbines as compared to I.C engines is
Higher
Lower
Same
None of the above
The output of a gas turbine is 300 KW and its efficiency is 20 percent, the heat supplied is
6000 KW
15 KW
600 KW
150 KW
Which of the following statement is correct?
The reciprocating compressors are best suited for high pressure and low volume capacity
The effect of clearance volume on power consumption is negligible for the same volume of discharge
Both (A) and (B)
None of these
The type of rotary compressor used in gas turbines, is of
Centrifugal type
Axial flow type
Radial flow type
None of these
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
Inter-cooling in gas turbine results in
Increase in net output but decrease in thermal efficiency
Increase in thermal efficiency but decrease in net output
Increase in both thermal efficiency and net output
Decrease in both thermal efficiency and net output
The thermodynamic efficiency of rotary compressor is based on
Isothermal compression
Adiabatic compression
Isentropic compression
Polytropic compression
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
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
The blades of gas turbine are made of
High nickel alloy
Stainless steel
Carbon steel
High alloy steel
The volumetric efficiency of a compressor
Increases with decrease in compression ratio
Decreases with decrease in compression ratio
Increases with increase in compression ratio
Decreases with increase in compression ratio
Volumetric efficiency of a compressor decreases with ________ in compression ratio.
Decrease
Increase
Remain same
Does not change
A jet engine has
No propeller
Propeller in front
Propeller at back
Propeller on the top
The air power of the compressor is also known as
Indicated power
Brake power
Frictional power
None of these
The compression ratio for the compressor is always __________ unity.
Equal to
Less than
More than
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
For maximum work, the reheating should be done to an intermediate pressure of (Where p₁ = Maximum pressure, and p₂ = Minimum pressure)
(p₁ - p₂)/2
(p₁ + p₂)/2
p₁/p₂
p₁ p₂
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
In air compressors, free air delivery means 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
High air-fuel ratio is used in gas turbines
To increase the output
To increase the efficiency
To save fuel
To reduce the exit temperature
Pick up the false statement
Gas turbine is a self starting unit
Gas turbine does not require huge quantity of water like steam plant
Exhaust losses in gas turbine are high due to large mass flow rate
Overall efficiency of gas turbine plant is lower than that of a reciprocating engine
The thrust of a jet propulsion power unit can be increased by
Injecting water into the compressor
Burning fuel after gas turbine
Injecting ammonia into the combustion chamber
All of the above
In which case the air-fuel ratio is likely to be maximum?
Gas turbine
4-stroke petrol engine
4-stroke diesel engine
Multi cylinder engine
Which of the following plants is smallest and lightest for generating a given amount of power?
Gas turbine plant
Petrol engine
Diesel engine
Solar plant
The ratio of workdone per cycle to the stroke volume of the compressor is known as
Compressor capacity
Compression ratio
Compressor efficiency
Mean effective pressure
In n₁ and n₂ are the indices of compression for the first and second stage of compression, then the ratio of workdone on the first and second stages (W₁/W₂) with perfect intercooling is given by
W₁/W₂ = n₂(n₁ - 1)/n₁(n₂ - 1)
W₁/W₂ = n₁(n₂ - 1)/n₂(n₁ - 1)
W₁/W₂ = n₁/n₂
W₁/W₂ = n₂/n₁
Aeroplanes employ following type of compressor
Radial flow
Axial flow
Centrifugal
None of the above