The mass of gas turbine per kW developed is about ________ as that of an I.C. engine.
Same
One-half
One fourth
One sixth
Correct Answer :
D. One sixth
Related Questions
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
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
Inter cooling in compressors
Cools the delivered air
Results in saving of power in compressing a given volume to given pressure
Is the standard practice for big compressors
Enables compression in two stages
The compressed air may be used
In gas turbine plants
For operating pneumatic drills
In starting and supercharging of I.C. engines
All of the above
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
Gas turbine works on
Brayton or Atkinson cycle
Carnot cycle
Rankine cycle
Erricson cycle
Pick up the correct statement
Large gas turbines use radial inflow turbines
Gas turbines have their blades similar to steam turbine
Gas turbine's blade will appear as impulse section at the hub and as a reaction section at tip
Gas turbines use both air and liquid cooling
If the clearance ratio for a reciprocating air compressor is 'K', then its volumetric efficiency is given by
1 - k + k (p₁/p₂)1/n
1 + k - k (p₂/p₁)1/n
1 - k + k (p₁/p₂) n- 1/n
1 + k - k (p₂/p₁) n-1/n
In open cycle turbojet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the
Thrust and range of aircraft
Efficiency of the engine
Both (A) and (B)
None of these
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
The assumption made in two stage compression with intercooler is that
There is no pressure drop in the intercooler
The compression in both the cylinders is polytropic
The suction and delivery of air takes place at constant pressure
All of the above
What will be the volume of air at 327°C if its volume at 27°C is 1.5 m³/ mt?
3 m³/ mt.
1.5 m³/ mt.
18 m³/ mt.
6 m³/ mt.
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
Adiabatic compression is one in which
Temperature during compression remains constant
No heat leaves or enters the compressor cylinder during compression
Temperature rise follows a linear relationship
Work done is maximum
The working fluid in a turbine is
In two phases
In three phases
In a single phase
In the form of air and water mixture
Propulsive efficiency is defined as ratio of
Thrust power and fuel energy
Engine output and propulsive power
Propulsive power and fuel input
Thrust power and propulsive power
It is not possible to use closed gas turbine cycle in aeronautical engines because
It is inefficient
It is bulky
It requires cooling water for its operation
None of the above
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 ratio of workdone per cycle to the stroke volume of the compressor is known as
Compressor capacity
Compression ratio
Compressor efficiency
Mean effective pressure
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
The pressure of air at the beginning of the compression stroke is ________ the atmospheric pressure.
Equal to
Less than
More than
None of these
The air is delivered ________ in one revolution in case of a three lobbed rotor.
Two times
Three times
Four times
Six times
Water is injected in gas turbine cycle to
Control temperature
Control output of turbine
Control fire hazards
Increase efficiency
In a turbo jet engine, subsequent to heat addition to compressed air, to get the power output, the working substance is expanded in
Exit nozzle, which is a constant volume process
Exit nozzle, which is essentially an isentropic process
Turbine blades, which is a constant volume process
Turbine blades, which is essentially an isentropic process
Ratio of indicated h.p. to shaft h.p. in known as
Compressor efficiency
Isothermal efficiency
Volumetric efficiency
Mechanical efficiency
In a centrifugal compressor, the ratio of the ________ to the blade velocity is called slip factor.
Inlet whirl velocity
Outlet whirl velocity
Inlet velocity of flow
Outlet velocity of flow
In the cross compounding of the gas turbine plant
H.P. compressor is connected to H.P. turbine and L.P. compressor to L.P. turbine
H.P. compressor is connected to L.P. turbine and L.P. compressor is connected to H.P. turbine
Both the arrangements can be employed
All are connected in series
Cylinder clearance in a compressor should be
As large as possible
As small as possible
About 50% of swept volume
About 100% of swept volume
The fuel consumption in gas turbines is accounted for by
Lower heating value
Higher heating value
Heating value
Higher calorific value
The velocity of air entering in a rocket is ________ as compared to an aircraft.
Zero
Less
More
Same