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Chemical Engineering :: Heat Transfer

  1. In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid

  2. A.
    varies directly as the area and the LMTD.
    B.
    directly proportional to LMTD and inversely proportional to the area.
    C.
    varies as square of the area.
    D.
    none of these.

  3. With increase in temperature, the total emissivity of conductors

  4. A.
    increases
    B.
    decreases
    C.
    remains same
    D.
    decreases linearly

  5. Loss of heat from untagged steam pipe to the ambient air is by

  6. A.
    conduction
    B.
    convection
    C.
    radiation
    D.
    all (a), (b) & (c)

  7. Fruit juice (a heat sensitive material) can be concentrated in a __________ evaporator.

  8. A.
    long tube
    B.
    falling film
    C.
    high pressure
    D.
    none of these

  9. Tubes are held between top and bottom tube sheets in Calenderia type evaporator by keeping

  10. A.
    both the tube sheets fixed.
    B.
    both the tube sheets floating.
    C.
    the top tube sheet floating and bottom tube sheet fixed.
    D.
    the top tube sheet fixed and the bottom tube-sheet floating.

  11. A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of

  12. A.
    2
    B.
    20.8
    C.
    20.2
    D.
    20.5

  13. Heat sensitive materials can be concentrated in an evaporator employing

  14. A.
    vacuum
    B.
    high pressure
    C.
    high residence time
    D.
    none of these

  15. A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires

  16. A.
    less heating surface.
    B.
    more space.
    C.
    lower maintenance cost.
    D.
    none of these.

  17. In a shell and tube heat exchanger, floating head is used for

  18. A.
    large temperature differentials.
    B.
    high heat transfer co-efficient.
    C.
    low pressure drop.
    D.
    less corrosion of tubes.

  19. Steam trap is used to

  20. A.
    condense the steam flowing in the pipeline.
    B.
    remove water resulting from partial condensation of steam.
    C.
    stop the supply of steam.
    D.
    none of these.