A rocket engine uses ________ for the combustion of its fuel.
Surrounding air
Compressed atmospheric air
Its own oxygen
None of these
Correct Answer :
C. Its own oxygen
Related Questions
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
In a jet engine, the air-fuel ratio is
30 : 1
40 : 1
50 : 1
60 : 1
Out of the following, from where you will prefer to take intake for air compressor
From an air conditioned room maintained at 20°C
From outside atmosphere at 1°C
From coal yard side
From a side where cooling tower is located nearby
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
The capacity of compressor will be highest when its intake temperature is
Lowest
Highest
Anything
Atmospheric
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
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
The thermal efficiency of a gas turbine as compared to a diesel plant is
Same
More
Less
Depends on other factors
The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation
0.1 %
0.5 %
1.0 %
5 %
Maximum temperature in a gas turbine is of the order of
700°C
2000°C
1500°C
1000°C
The ratio of isentropic work to Eulers work is known as
Compressor efficiency
Isentropic efficiency
Euler's efficiency
Pressure coefficient
The overall isothermal efficiency of compressor is defined as the ratio of
Isothermal h.p. to the BHP of motor
Isothermal h.p. to adiabatic h.p.
Power to drive compressor to isothermal h.p.
Work to compress air isothermally to work for actual compression
The air entry velocity m a rocket as compared to aircraft is
Same
More
Less
Zero
1 m of air at atmospheric condition weighs approximately
0.5 kg
1.0 kg
1.3 kg
2.2 kg
Standard air is the air at
Atmospheric conditions at any specific location
20°C and 1 kg/cm² and relative humidity 36%
0°C and standard atmospheric conditions
15°C and 1 kg/cm²
A rotary compressor is driven by an
Electric motor
Engine
Either (A) or (B)
None of these
An ideal air compressor cycle without clearance on PV diagram can be represented by following processes
One adiabatic, two isobaric, and one constant volume
Two adiabatic and two isobaric
Two adiabatic, one isobaric and one constant volume
One adiabatic, one isobaric and two constant volumes
In jet engines the products of combustion after passing through the gas turbine are discharged into
Atmosphere
Back to the compressor
Discharge nozzle
Vacuum
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
The following property is most important for material used for gas turbine blade
Toughness
Fatigue
Creep
Corrosion resistance
For perfect intercooling in a two stage compressor
p₂/p₁ = p₃/p₂
p₁/p₃ = p₂/p₁
p₁ = p₃
p₁ = p₂ p₃
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
In turbo fan engine, the jet velocity as compared to turbojet engine is
Less
More
Same
May be less or more depending upon speed
The efficiency of roots blower ________ with the increase in pressure ratio.
Decreases
Increases
Does not change
None of these
The efficiency of the vane blower is (where W₁ = Workdone due to compression, and W₂ = Workdone due to back flow)
W₁/(W₁ + W₂)
W₂/(W₁ + W₂)
(W₁ + W₂)/W₁
(W₁ + W₂)/W₂
A compressor at high altitudes will require ________ power.
Same
Less
More
None of these
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 thrust on the rotor in a centrifugal compressor is produced by
Radial component
Axial component
Tangential component
None of the above
Gas turbine as compared to internal combustion engine
Can be driven at a very high speed
Produces uniform torque
Has more efficiency
All of these
An aftercooler is used to
Remove impurities from air
Reduce volume of air
Cause moisture and oil vapour to drop out
Cool the air