A simple turbojet engine is basically
A propeller system
Gas turbine engine equipped with a propulsive nozzle and diffuse
Chemical rocket engine
Ramjet engine
Correct Answer :
B. Gas turbine engine equipped with a propulsive nozzle and diffuse
Related Questions
In air breathing jet engine, the jet is formed by expanding
Highly heated atmospheric air
Solids
Liquid
Plasma
A jet engine has
No propeller
Propeller in front
Propeller at back
Propeller on the top
The gas in cooling chamber of a closed cycle gas turbine is cooled at
Constant volume
Constant temperature
Constant pressure
None of these
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
If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix I and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity
Vi = Vo
Vt > Vo
U < Vo
V = Uo
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 reason for volumetric efficiency of reciprocating compressor being less than 100 percent is
Pressure drop across the valves
Superheating in compressor
Clearance volume and leakages
All of these
Gas turbine works on
Brayton or Atkinson cycle
Carnot cycle
Rankine cycle
Erricson cycle
Volumetric efficiency of air compressors is of the order of
20 - 30 %
40 - 50 %
60 - 70 %
70 - 90 %
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
A rocket engine for the combustion of its fuel
Carries its own oxygen
Uses surrounding air
Uses compressed atmospheric air
Does not require oxygen
The efficiency of jet engine is
Lower at low speed
Higher at high altitudes
Same at all altitudes
Higher at high speed
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
The temperature of air at the beginning of the compression stroke is ________ the atmospheric temperature.
Equal to
Less than
More than
None of these
The ratio of isentropic work to Euler work is known as
Pressure coefficient
Work coefficient
Polytropic reaction
Slip factor
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
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
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
A rotary compressor is driven by an
Electric motor
Engine
Either (A) or (B)
None of these
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
The ratio of the discharge pressure to the inlet pressure of air is called
Compression ratio
Expansion ratio
Compressor efficiency
Volumetric efficiency
The pressure ratio in gas turbines is of the order of
2 : 1
4 :1
61 : 1
9 : 1
In a reciprocating air compressor, the compression work per kg of air
Increases as clearance volume increases
Decreases as clearance volume increases
Is independent of clearance volume
Increases as clearance volume decreases
In a closed cycle gas turbine, the air is compressed
Isothermally
Polytropically
Isentropically
None of these
Gas turbines use following type of air compressor
Centrifugal type
Reciprocating type
Lobe type
Axial flow type
The material commonly used for air craft gas turbine is
Stainless steel
High alloy steel
Duralumin
Timken, Haste alloys
The thrust on the rotor in a centrifugal compressor is produced by
Radial component
Axial component
Tangential component
None of the above
The blades of gas turbine are made of
High nickel alloy
Stainless steel
Carbon steel
High alloy steel
A rocket engine uses ________ for the combustion of its fuel.
Surrounding air
Compressed atmospheric air
Its own oxygen
None of these
1 m of air at atmospheric condition weighs approximately
0.5 kg
1.0 kg
1.3 kg
2.2 kg