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Chemical Engineering :: Heat Transfer

  1. In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger.

  2. A.
    once
    B.
    twice
    C.
    thrice
    D.
    four times

  3. When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is

  4. A.
    free convection
    B.
    entry length problem in laminar forced conduction (developing thermal boundary layer)
    C.
    mixed convection (both free and forced)
    D.
    forced convection

  5. The purpose of providing bleed points in the evaporator is to

  6. A.
    admit the feed
    B.
    remove the product
    C.
    facilitate removal of non-condensable gases
    D.
    create vacuum

  7. Water always boils when its

  8. A.
    temperature reaches 100° C.
    B.
    vapour pressure equals 76 cm of Hg.
    C.
    saturated vapour pressure equals the external pressure on its surface.
    D.
    saturated vapour pressure is less than the atmospheric pressure.

  9. A multiple effect evaporator as compared to a single effect evaporator of the same capacity has

  10. A.
    lower heat transfer area.
    B.
    lower steam economy.
    C.
    higher steam economy.
    D.
    higher solute concentration in the product.

  11. Which is the most suitable for cold viscous feed?

  12. A.
    Forward feed
    B.
    Backward feed
    C.
    Mixed feed
    D.
    Parallel feed

  13. Dropwise condensation is promoted on a/an __________ surface.

  14. A.
    glazed
    B.
    oily
    C.
    coated
    D.
    smooth

  15. At Pr > 1, conduction in an ordinary fluid flowing through a heated pipe is limited to the

  16. A.
    buffer zone
    B.
    turbulent core
    C.
    both (a) and (b)
    D.
    viscous sub-layer

  17. In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.

  18. A.
    increases
    B.
    decreases
    C.
    remains constant
    D.
    may increase or decrease, depends on the vacuum

  19. is called the __________ number

  20. A.
    Peclet
    B.
    Stanton
    C.
    Graetz
    D.
    none of these