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Chemical Engineering :: Heat Transfer

  1. Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by
    This is valid for the value of NRe equal to

  2. A.
    < 2100
    B.
    2100-4000
    C.
    > 4000
    D.
    > 10000

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  3. Steam side heat transfer co-efficient in an evaporator is in the range of __________ kcal/hr.m2°C.

  4. A.
    10-50
    B.
    100-500
    C.
    1000-1500
    D.
    5000-15000

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  5. Correction is applied to LMTD for __________ flow.

  6. A.
    parallel
    B.
    counter
    C.
    cross
    D.
    none of these

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  7. If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is

  8. A.
    always less than h1
    B.
    always between h1 and h2
    C.
    always higher than h2
    D.
    dependent on metal resistance

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  9. One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to

  10. A.
    heat the water from 0°C to 100°C.
    B.
    evaporate the water.
    C.
    to superheat the steam.
    D.
    data insufficient, can't be predicted

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  11. For __________ Prandtl number values, the heat conduction will be negligible in the buffer zone.

  12. A.
    extremely low
    B.
    low
    C.
    high
    D.
    no

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  13. The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2. The flux, when the element temperature is increased to 1000°C for the same furnace temperature is

  14. A.
    11.2 kW/m2
    B.
    12.0 kW/m2
    C.
    14.6 kW/m2
    D.
    16.5 kW/m2

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  15. Heat exchangers operating, when the asymptotic range is reached,

  16. A.
    provide very large heat transfer co-efficient.
    B.
    results in making part of the heating surface inactive.
    C.
    results in abruptly increased velocity.
    D.
    none of these.

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  17. In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell)

  18. A.
    D/5 and D
    B.
    D/2 and 2 D
    C.
    D/4 and 2 D
    D.
    D and 2 D

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  19. In case of heat transfer by conduction in a hollow cylinder, __________ mean area is used to calculate the heat transfer rate.

  20. A.
    geometric
    B.
    arithmetic
    C.
    logarithmic
    D.
    either (a), (b) or (c)

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