Effects of variable physical properties on laminar film condensation of saturated steam on a vertical flat plate

Abstract

A theoretical study is made of steady two-dimensional laminar film condensation of pure saturated steam at 100°C and atmospheric pressure on an isothermal vertical wall. The variable physical properties of the liquid condensate are taken to be those of saturated water at the appropriate temperatures. On neglecting the effects of surface tension at the liquid-vapour interface the governing equations for the liquid and vapour phases are simplified, using boundary-layer approximations, and admit to a solution in terms of similarity variables. From numerical solutions of the resulting ordinary differential equations flow characteristics for the liquid and vapour phases are determined for the wall temperatures 0, 10, 40, 70 and 90°C. The related results on wall heat transfer and mass flow in the liquid phase are presented and compared in detail with those from existing theories.