A Study on the Process of Drop Growth by Coalescence during Dropwise Condensation

Abstract

The process of drop growth due to both direct condensation of vapor onto the drop and coalescence with neighboring droplets during dropwise condensation is investigated.Obviously it is the process of coalescence that largely controls the rate of drop growth and, eventually, the rate of condensation, but the random or stochastic nature of this process has prevented us from conquering the problem.In this paper, some analytical considerations are made of this complicated process, and mathematical expressions which relate the rate of growth of each individual droplet, together with the distribution of drop size over the condensing surface, to the macroscopic heat-treansfer coefficient are derived.Also the method of computer simulation, which the authors have developed in their previous works, is successfully employed to determine the parameters of the growth process.