A jet engine works on the principle of conservation of
Mass
Energy
Flow
Linear momentum
Correct Answer :
D. Linear momentum
Related Questions
Pick up the correct statement
Closed cycle gas turbine is an I.C engine
Gas turbine uses same working fluid over and over again
Ideal efficiency of closed cycle gas turbine plant is more than Carnot cycle efficiency
Thrust in turbojet is produced by nozzle exit gases.
In turbo fan engine, the jet velocity as compared to turbojet engine is
Less
More
Same
May be less or more depending upon speed
In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of
Vacuum
Atmospheric air
Compressed air
Oxygen alone
The volume of air delivered in a medium capacity air compressor per unit time is
0.1 to 1.2 m³/s
0.15 to 5 m³/s
Above 5 m³/s
None of these
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
The degree of reaction is usually kept ________ for all types of axial flow compressors.
0.2
0.3
0.4
0.5
The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called
Slip factor
Velocity factor
Velocity coefficient
None of the above
The inlet pressure is always ________ the discharge pressure.
Equal to
Less than
More than
None of these
A jet engine has
No propeller
Propeller in front
Propeller at back
Propeller on the top
In a centrifugal compressor, an increase in speed at a given pressure ratio causes
Increase in flow
Decrease in flow
Increase in efficiency
Increase in flow and decrease in efficiency
There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would
Remain same
Decrease
Increase
None of the above
Which is false statement about advantages of multistage compressor in comparison to single stage compressor?
Less power requirement
Better mechanical balance
Less loss of air due to leakage past the cylinder
Lower volumetric efficiency
Efficiency of gas turbine is increased by
Reheating
Inter cooling
Adding a regenerator
All of the 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
For slow speed large capacity compressor, following type of valve will be best suited
Poppet valve
Mechanical valve of the Corliss, sleeve, rotary or semi rotary type
Disc or feather type
Any of the above
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
A compressor at high altitudes will require ________ power.
Same
Less
More
None of these
Isothermal compression efficiency, even when running at high speed, can be approached by using
Multistage compression
Cold water spray
Both (A) and (B) above
Fully insulating the cylinder
The ratio of the indicated power to the shaft power or brake power of the motor or engine required to drive the compressor, is called
Compressor efficiency
Volumetric efficiency
Isothermal efficiency
Mechanical efficiency
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
Aeroplanes employ following type of compressor
Radial flow
Axial flow
Centrifugal
None of the above
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
The air power of the compressor is also known as
Indicated power
Brake power
Frictional power
None of these
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
The capacity of compressor will be highest when its intake temperature is
Lowest
Highest
Anything
Atmospheric
Pick up the wrong statement
Pulsejet requires no ambient air for propulsion
Ramjet engine has no turbine
Turbine drives compressor in a Turbojet
Bypass turbojet engine increases the thrust without adversely affecting, the propulsive efficiency and fuel economy
The ratio of specific weight/h.p. of gas turbine and I.C engines may be typically of the order of
1 : 1
2 : 1
4 : 1
1 : 6
In jet propulsion power unit, the inlet duct of diverging shape is used in order to
Collect more air
Convert kinetic energy of air into pressure energy
Provide robust structure
Beautify the shape
The fuel consumption in gas turbines is accounted for by
Lower heating value
Higher heating value
Heating value
Higher calorific value
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