Complete Similarity Mathematical Models on Laminar Forced Film Condensation of Pure Vapour

Abstract

The new similarity analysis method is successfully applied in this work, and a complete similarity mathematical model is developed on the laminar forced film condensation of superheated and saturated vapours with consideration of variable physical properties. The laminar forced convection film condensation (for short, the laminar forced film condensation, the same below) with two-phase film flow consists of the condensate liquid film and vapour film, and in both film flows, the variable physical properties are considered. For model of the condensate liquid film, the determination of the similarity variables and consideration of the variable physical properties are based on the approach in Chap. 8 for liquid laminar forced convection, while for the model of the vapour film the proposal of the similarity variables and consideration of the variable physical properties are based on Chap. 7 for gas laminar forced convection. The two models are combined with the five interfacial matching balance equations, respectively describing the velocity component continuity, mass flow rate continuity, the balance of shear force, the energy balance, and the temperature continuity. Based on the new similarity analysis method, the developed system of complete similarity dimensionless model provides convenience for treatment of variable physical properties and solution.