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Chemical Engineering :: Heat Transfer

  1. Kirchoff s law applies to __________ radiation.

  2. A.
    total
    B.
    monochromatic
    C.
    both (a) & (b)
    D.
    neither (a) nor (b)

  3. With the increase of temperature, the Col-burn jH factor

  4. A.
    increases.
    B.
    decreases.
    C.
    remains unchanged.
    D.
    may increase or decrease ; depending on temperature.

  5. In case of evaporators, liquid entrainment results primarily due to

  6. A.
    high vacuum in the evaporator.
    B.
    high evaporation rate.
    C.
    foaming of the solution.
    D.
    high heat transfer rate.

  7. Baffles in the shell side of a shell and tube heat exchanger

  8. A.
    increase the cross-section of the shell side liquid.
    B.
    force the liquid to flow parallel to the bank.
    C.
    increase the shell side heat transfer co-efficient.
    D.
    decrease the shell side heat transfer co-efficient.

  9. Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is

  10. A.
    finned tube heat exchanger with air inside and steam outside.
    B.
    finned tube heat exchanger with air outside and steam inside.
    C.
    shell and tube heat exchanger with air inside tubes and steam on shell side.
    D.
    shell and tube heat exchanger with air on shell side and steam inside tubes.

  11. The unit of heat transfer co-efficient in SI unit is

  12. A.
    J/M2°K
    B.
    W/m2°K
    C.
    W/m°K
    D.
    J/m°K

  13. The number of kg vaporised per kg of steam fed to the evaporator is defined as

  14. A.
    capacity
    B.
    rate of evaporation
    C.
    economy
    D.
    rate of vaporisation

  15. Pick out the wrong statement.

  16. A.
    In case of heat transfer by purely forced convection, GR/Re2 ≤ 1.
    B.
    The equivalent diameter of heat transfer for a duct of square cross-section (having each side as 'x') is equal to 4x.
    C.
    Distillation process is not the same as evaporation.
    D.
    The effectiveness of nucleate boiling depends basically on the ease with which the bubbles are formed and detached from the heating surface.

  17. Economy of a multiple effect evaporator is not influenced much by the

  18. A.
    boiling point elevations
    B.
    temperature of the feed
    C.
    rate of heat transfer
    D.
    ratio of the weight of the thin liquor to thick liquor

  19. Increasing the liquor level in the evaporator results in the

  20. A.
    decreased capacity.
    B.
    increase in liquor film co-efficient.
    C.
    decreased effect of hydrostatic head.
    D.
    increased true temperature drop.