The interaction effects between droplets condensing from moist air using a distributed point sink method

Insititute of Thermal Engineering, TU Bergakademie Freiberg, 09599 Freiberg, Germany

^* Corresponding author: shaofei.zheng@ttd.tu-freiberg.de

Abstract

In modelling dropwise condensation, growth of the droplet is frequently assumed in an isolated form. However, for dropwise condensation of moist air the vapor diffusion from the surrounding to the droplet surface will be tremendously influenced by the blocking effect of the neighboring droplets. The influenced spatial distribution of water vapor totally determines a different condensation rate comparing with that by the isolated droplet model. In this work, a distributed point method (DPSM) as the methodof Green function is developed to capture the interaction effects of droplets without requiring solution of the diffusion equation and the numerical discretization. Due to its nature, the automaticallysatisfied boundary conditions make sure the solution accuracy based on the uniqueness theorem. The significant characteristics for the interaction effects between droplets are investigated by handling a series of droplet arrays. During dropwise condensation, a typical droplet array containing up to 1000 droplets is considered. The results indicate that the interaction effect between droplets is critical in accurately predicting the condensation behavior for dropwise condensation in the presence of non-condensable gas.