Compressors MCQ

Test your knowledge with important Compressors MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more Compressors MCQs at Bissoy

• Aeroplanes employ following type of compressor
  ক

  Radial flow

  খ

  Axial flow

  গ

  Centrifugal

  ঘ

  None of the above
• A closed cycle gas turbine gives ________ efficiency as compared to an open cycle gas turbine.
  ক

  Same

  খ

  Lower

  গ

  Higher

  ঘ

  None of these
• The ratio of specific weight/h.p. of gas turbine and I.C. engines may be typically of the order of
  ক

  1 : 1

  খ

  2 : 1

  গ

  4 : 1

  ঘ

  1 : 6
• The volumetric efficiency of a compressor
  ক

  Increases with decrease in compression ratio

  খ

  Decreases with decrease in compression ratio

  গ

  Increases with increase in compression ratio

  ঘ

  Decreases with increase in compression ratio
• A rocket works with maximum overall efficiency when air craft velocity is equal to the
  ক

  Jet velocity

  খ

  Twice the jet velocity

  গ

  Half the jet velocity

  ঘ

  Average of the jet velocity
• If the flow of air through the compressor is perpendicular to its axis, then it is a
  ক

  Reciprocating compressor

  খ

  Centrifugal compressor

  গ

  Axial flow compressor

  ঘ

  Turbo compressor
• Mining industry usually employs following motive power
  ক

  A.C. electric motor

  খ

  Compressed air

  গ

  Petrol engine

  ঘ

  Diesel engine
• When air is to be compressed at a high pressure, then it is advantageous to use
  ক

  Single stage compression

  খ

  Multistage compression without intercooling

  গ

  Multistage compression with intercooling

  ঘ

  None of these
• For speed above 3000 km/hour, it is more advantageous to use
  ক

  Turbojet engine

  খ

  Ramjet engine

  গ

  Propellers

  ঘ

  Rockets
• Which is false statement about air receivers?
  ক

  These are used to dampen pulsations

  খ

  These act as reservoir to take care of sudden demands

  গ

  These increase compressor efficiency

  ঘ

  These knock out some oil and moisture
• In turbo fan engine, the jet velocity as compared to turbojet engine is
  ক

  Less

  খ

  More

  গ

  Same

  ঘ

  May be less or more depending upon speed
• Reheating in multistage expansion gas turbine results in
  ক

  High thermal efficiency

  খ

  Reduction in compressor work

  গ

  Decrease of heat loss in exhaust

  ঘ

  Maximum work output
• Reheating in gas turbine results in
  ক

  Increase of work ratio

  খ

  Decrease of thermal efficiency

  গ

  Decrease of work ratio

  ঘ

  Both (A) and (B) above
• Inter-cooling in gas turbine results in
  ক

  Increase in net output but decrease in thermal efficiency

  খ

  Increase in thermal efficiency but decrease in net output

  গ

  Increase in both thermal efficiency and net output

  ঘ

  Decrease in both thermal efficiency and net output
• If infinite number of heaters be used in a gas turbine, then expansion process in turbine approaches
  ক

  Isothermal

  খ

  Isentropic

  গ

  Adiabatic

  ঘ

  Isochoric
• As the turbine inlet temperature increases, the thermal efficiency of gas turbine for the optimum pressure ratio
  ক

  Increases

  খ

  Decreases

  গ

  Remain same

  ঘ

  First increases and then decreases
• To avoid moisture troubles, the branch connections from compressed air lines should be taken from
  ক

  Top side of main

  খ

  Bottom side of main

  গ

  Left side of main

  ঘ

  Right side of main
• Which of the following statement is correct as regard to centrifugal compressors?
  ক

  The flow of air is parallel to the axis of the compressor

  খ

  The static pressure of air in the impeller increases in order to provide centripetal force on the air

  গ

  The impeller rotates at high speeds

  ঘ

  The maximum efficiency is higher than multistage axial flow compressors
• Standard air is the air at ________ and relative humidity of 36 percent.
  ক

  0.1 bar and 20°C

  খ

  1 bar and 20°C

  গ

  0.1 bar and 40°C

  ঘ

  1 bar and 40°C
• Ram compression in turbojet involves
  ক

  Reduction of speed of incoming air and conversion of part of it into pressure energy

  খ

  Compression of inlet air

  গ

  Increasing speed of incoming air

  ঘ

  Lost work
• Which of the following fuels can be used in turbojet engines?
  ক

  Liquid hydrogen

  খ

  High speed diesel oil

  গ

  Kerosene

  ঘ

  Methyl alcohol
• The maximum combustion pressure in gas turbine as compared to I.C. engine is
  ক

  More

  খ

  Less

  গ

  Same

  ঘ

  Depends on other factors
• Mechanical efficiency of gas turbines as compared to I.C. engines is
  ক

  Higher

  খ

  Lower

  গ

  Same

  ঘ

  None of the above
• Separators in compressor installations are located
  ক

  Before inter-cooler

  খ

  After inter-cooler

  গ

  After receiver

  ঘ

  Between after-cooler and air receiver
• A rocket engine uses __________ for the combustion of its fuel.
  ক

  Surrounding air

  খ

  Compressed atmospheric air

  গ

  Its own oxygen

  ঘ

  None of these
• Stalling of blades in axial flow compressor is the phenomenon of
  ক

  Air stream blocking the passage

  খ

  Motion of air at sonic velocity

  গ

  Unsteady periodic and reversed flow

  ঘ

  Air stream not able to follow the blade contour
• Surging is the phenomenon of
  ক

  Air stream blocking the passage

  খ

  Motion of air at sonic velocity

  গ

  Unsteady, periodic and reversed flow

  ঘ

  Air stream not able to follow the blade contour
• If the flow of air through the compressor is parallel to its axis, then the compressor is
  ক

  Reciprocating compressor

  খ

  Centrifugal compressor

  গ

  Axial flow compressor

  ঘ

  Turbo compressor
• The following is true for an open cycle gas turbine having exhaust heat exchanger. Atmospheric air before entering the compressor is
  ক

  Heated

  খ

  Compressed air before entering the combustion chamber is heated

  গ

  Bled gas from turbine is heated and readmitted for complete expansion

  ঘ

  Exhaust gases drive the compressor
• Which is false statement about multistage compression?
  ক

  Power consumption per unit of air delivered is low

  খ

  Volumetric efficiency is high

  গ

  It is best suited for compression ratios around 7 : 1

  ঘ

  The moisture in air is condensed in the inter-cooler