Heat Transfer From Condensing Vapors
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When a saturated vapor is brought into contact with a cool surface, heat is transferred to the surface and a liquid condenses.
HEAT TRANSFER FROM CONDENSING
VAPORS
When
a saturated vapor is brought into contact with a cool surface, heat is
transferred to the surface and a liquid condenses. The vapor may consist of a
single substance or a mixture, some components of which may be non-condensable.
The
process is described by the following sequence: The vapor diffuses to the
boundary where actual condensation takes place. In most cases, the con-densate
forms a continuous layer over the cooling surface, draining under the influence
of gravity. This is known as film condensation. The latent heat liberated is
transferred through the film to the surface by conduction. Although this film
offers considerable resistance to heat flow, film coefficients are usually
high.
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