Velocity and Temperature Fields on Laminar Forced Film Condensation of Pure Vapour

Abstract

The laminar forced film condensation of water vapour is taken as an example for treatment of variable physical properties. The temperature parameter method with the simple power-law equations for gases is used for the treatment of vapour film variable physical properties, and the water polynomial formulations are applied for the treatment of liquid film variable physical properties. Then, an effective numerical procedure is developed for rigorously satisfying a set of the interfacial physical matching conditions. On this basis, a system of the numerical solutions on the velocity and temperature fields of the two-phase film flows is rigorously found out. These numerical solutions demonstrate that increasing the wall subcooled grade causes increase of the condensate liquid film thickness but decrease of vapour film thickness, decrease of the wall temperature gradient but increase of the vapour film temperature gradient, and increase of the interfacial velocity level. Compared with the effect of the wall subcooled grade on these physical variables, the effect of the vapour subcooled grade is very slight.