The compressor performance at higher altitude compared to sea level will be
Same
Higher
Lower
Dependent on other factors
Correct Answer :
C. Lower
Related Questions
The ratio of the discharge pressure to the inlet pressure of air is called
Compression ratio
Expansion ratio
Compressor efficiency
Volumetric efficiency
The indicated work per unit mass of air delivered is
Directly proportional to clearance volume
Greatly affected by clearance volume
Not affected by clearance volume
Inversely proportional to clearance volume
In a closed cycle gas turbine, the air is compressed
Isothermally
Polytropically
Isentropically
None of these
In an axial flow compressor, the ratio of pressure in the rotor blades to the pressure rise in the compressor in one stage is known as
Work factor
Slip factor
Degree of reaction
Pressure coefficient
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
The following property is most important for material used for gas turbine blade
Toughness
Fatigue
Creep
Corrosion resistance
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
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
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
During base load operation, the best method of controlling compressor is
Start-stop motor
Constant speed unloader
Relief valve
Variable speed
The advantage of multistage compression over single stage compression is
Lower power consumption per unit of air delivered
Higher volumetric efficiency
Decreased discharge temperature
All of the above
The power available for takeoff and climb in case of turbojet engine as compared to reciprocating engine is
Less
More
Same
May be less or more depending on ambient conditions
More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than
2 kg/cm²
6 kg/cm²
10 kg/cm²
14.7 kg/cm²
Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
Backward curved blades has poor efficiency
Backward curved blades lead to stable performance
Forward curved blades has higher efficiency
Forward curved blades produce lower pressure ratio
For an irreversible gas turbine cycle, the efficiency and work ratio both depend on
Pressure ratio alone
Maximum cycle temperature alone
Minimum cycle temperature alone
Both pressure ratio and maximum cycle temperature
The inlet pressure is always ________ the discharge pressure.
Equal to
Less than
More than
None of these
Ratio of indicated H.P. and brake H.P. is known as
Mechanical efficiency
Volumetric efficiency
Isothermal efficiency
Adiabatic efficiency
The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as
Compressor efficiency
Volumetric efficiency
Isothermal efficiency
Mechanical efficiency
A closed cycle gas turbine works on
Carnot cycle
Rankine cycle
Ericsson cycle
Joule cycle
Gas turbine blades are given a rake
Equal to zero
In the direction of motion of blades
Opposite to the direction of motion of blades
Depending on the velocity
As the turbine inlet temperature increases, the thermal efficiency of gas turbine for the optimum pressure ratio
Increases
Decreases
Remain same
First increases and then decreases
The work ratio of a gas turbine plant is defined as the ratio of
Net work output and heat supplied
Net work output and work done by turbine
Actual heat drop and isentropic heat drop
Net work output and isentropic heat drop
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
The workdone on a compressor will be minimum if air is taken from
The atmosphere
A source at 0°C
A source of low temperature air
A source of high temperature air
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
When the outlet angle from the rotor of a centrifugal compressor is more than 90°, then the blades are said to be
Forward curved
Backward curved
Radial
None of these
High air-fuel ratio in gas turbines
Increases power output
Improves thermal efficiency
Reduces exhaust temperature
Do not damage turbine blades
Fighter bombers use following type of engine
Turbojet
Turbo-propeller
Rocket
Ramjet
Which of the following statement is wrong?
In a two stage reciprocating air compressor with complete intercooling, maximum work is saved.
The minimum work required for a two stage reciprocating air compressor is double the work required for each stage.
The ratio of the volume of free air delivery per stroke to the swept volume of the piston is called volumetric efficiency.
None of the above
The compression ratio in a gas turbine is of the order of
3.5 : 1
5 : 1
8 : 1
12 : 1