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Chemical Engineering :: Heat Transfer

  1. For a laminar flow of fluid in a circular tube, 'h1' is the convective heat transfer co-efficient at velocity 'V1'. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is

  2. A.
    1.26 h1
    B.
    0.794 h1
    C.
    0.574 h1
    D.
    1.741 h1

  3. The main purpose of providing fins on heat transfer surface is to increase the

  4. A.
    temperature gradient.
    B.
    mechanical strength of the equipment.
    C.
    heat transfer area.
    D.
    heat transfer co-efficient.

  5. A BTU/hr.ft.2 °F is equal to

  6. A.
    1 kcal/hr. m2°C.
    B.
    4.88 kcal/hr. m.2°C.
    C.
    1 kcal/hr. m2.°K.
    D.
    none of these.

  7. Which of the following has the lowest Prandtl number ?

  8. A.
    Molten sodium (a coolant used in fast breeder reactor)
    B.
    Water
    C.
    Transformer oil
    D.
    Dilute H2SO4

  9. In SI units, fouling factor is expressed in

  10. A.
    m2°K/W
    B.
    W/m2°K
    C.
    m2°K
    D.
    m°K/W

  11. An ejector is used to

  12. A.
    increase pressure
    B.
    increase temperature
    C.
    remove condensate
    D.
    none of these

  13. Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the

  14. A.
    less corrosion problems.
    B.
    flexibility possible in the baffle arrangement.
    C.
    low pressure drop.
    D.
    high heat transfer co-efficient.

  15. All analogy equations connecting friction factor and heat transfer co-efficient apply only to

  16. A.
    wall or skin friction
    B.
    form friction
    C.
    both (a) and (b)
    D.
    turbulent flow

  17. Electro-magnetic spectrum range, which is important for radiation varies from __________ microns.

  18. A.
    1 to 100
    B.
    0.5 to 50
    C.
    10 to 100
    D.
    100 to 1000

  19. The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are

  20. A.
    Re.Gz
    B.
    Nu, Pr
    C.
    Nu, Pr, Re
    D.
    Nu, Gz