LONGITUDINAL HEAT-CONDUCTION EFFECTS ON A VERTICAL THIN-PLATE IN A STEADY LAMINAR CONDENSATION PROCESS

In this paper, we analyze the steady-state condensation process of a s aturated vapor in contact with one side of a vertical thin plate, caus ed by an uniform cooling rate on the other surface of the plate. The e ffects of both longitudinal and transverse heat conduction in the plat e are considered. The momentum and energy balance equations are reduce d to a system of three differential equations with four parameters: th e Prandtl (Pr) and Jakob (Ja) numbers, a nondimensional plate thermal conductivity alpha, and the aspect ratio of the plate epsilon. To obta in the evolution of the condensed layer thickness and the related temp erature of the plate as a function of the longitudinal coordinate posi tion, the coupled balance equations are integrated in the asymptotic l imit Ja --> O, including the cases of very good and poor conducting pl ates. The results obtained indicate that the effect of the longitudina l heat conduction through the plate on the condensed layer thickness c hanges from a profile x(1/4) for a good conducting plate to x(1/3) for a poor conducting plate.