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Mechanical Engineering :: Compressors, Gas Turbines and Jet Engines

  1. Losses in a centrifugal compressor are due to

  2. A.

     Inlet losses

    B.

     Impeller channel losses

    C.

     Diffuser losses

    D.

     All of the above


  3. Pick up wrong statement. Surging phenomenon in centrifugal compressor depends on

  4. A.

     Mass flow rate

    B.

     Pressure ratio

    C.

     Change in load

    D.

     Stagnation pressure at the outlet


  5. Diffuser in a compressor is used to

  6. A.

     Increase velocity

    B.

     Make the flow streamline

    C.

     Convert pressure energy into kinetic energy

    D.

     Convert kinetic energy into pressure energy


  7. A large clearance volume in a reciprocating compressor results in

  8. A.

     Reduced volume flow rate

    B.

     Increased volume flow rate

    C.

     Lower suction pressure

    D.

     Lower delivery pressure


  9. 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

  10. A.

     Compressor efficiency

    B.

     Volumetric efficiency

    C.

     Isothermal efficiency

    D.

     Mechanical efficiency


  11. Volumetric efficiency is

  12. A.

     The ratio of stroke volume to clearance volume

    B.

     The ratio of the air actually delivered to the amount of piston displacement

    C.

     Reciprocal of compression ratio

    D.

     Index of compressor performance


  13. In air breathing jet engine, the jet is formed by expanding

  14. A.

     Highly heated atmospheric air

    B.

     Solids

    C.

     Liquid

    D.

     Plasma


  15. In a four stage compressor, if the pressure at the first and third stage is 1 bar and 16 bar, then the delivery pressure at the fourth stage will be

  16. A.

     1 bar

    B.

     16 bar

    C.

     64 bar

    D.

     256 bar


  17. Reciprocating air compressor is best suited for

  18. A.

     Large quantity of air at high pressure

    B.

     Small quantity of air at high pressure

    C.

     Small quantity of air at low pressure

    D.

     Large quantity of air at low pressure


  19. Rotary compressor is best suited for

  20. A.

     Large quantity of air at high pressure

    B.

     Small quantity of air at high pressure

    C.

     Small quantity of air at low pressure

    D.

     Large quantity of air at low pressure