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Mechanical Engineering :: Compressors,Gas Dynamics and Gas Turbines

  1. The volume of air sucked by the compressor during its suction stroke is called

  2. A.
    free air delivery
    B.
    compressor capacity
    C.
    swept volume
    D.
    none of these

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  3. For perfect intercooling in a two stage compressor,

  4. A.
    B.
    C.
    p1 = p3
    D.
    p1 = p2 p3

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  5. The efficiency of the vane blower is (where W1 = Workdone due to compression, and W2 = Workdone due to back flow)

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  7. The volumetric efficiency of a compressor

  8. A.
    constant with decrease in compression ratio
    B.
    decreases with decrease in compression ratio
    C.
    increases with increase in compression ratio
    D.
    decreases with increase in compression ratio

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  9. Reheating in a multi-stage expansion gas turbine __________ compressor work.

  10. A.
    has no effect on
    B.
    decreases
    C.
    increases

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  11. The multi-stage compression ofair as compared to single stage compression

  12. A.
    improves volumetric efficiency for the given pressure ratio
    B.
    reduces workdone per kg of air
    C.
    gives more uniform torque
    D.
    all of these

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  13. Which one of the following is the effect of blade shape on performance of a centrifugal compressor ?

  14. A.
    Backward curved blades has poor efficiency
    B.
    Backward curved blades lead to stable performance
    C.
    Forward curved blades has higher efficiency
    D.
    Forward curved blades produce lower pressure ratio

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  15. In a jet engine, the air-fuel ratio is

  16. A.
    30:1
    B.
    40:1
    C.
    50:1
    D.
    60:1

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  17. Which of the following bladings will give maximum pressure rise in a centrifugal compressor, assuming the same overall dimensions, blade inlet angle and rotational speeds ?

  18. A.
    Forward curved blades
    B.
    Backward curved blades
    C.
    Radial blades
    D.
    all of these

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  19. In an axial flow compressor, the ratio of pressure in theTOtor blades to the pressure rise in the compressor in one stage is known as

  20. A.
    work factor
    B.
    slip factor
    C.
    degree of reaction
    D.
    pressure coefficient

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