Numerical modelling of dropwise condensation of water vapor from humid air using point sink superposition method

Abstract

On a subcooled hydrophobic surface, the water vapor from humid air condenses into discrete liquid droplets and grows over time. The water vapor concentration field of the droplets in their immediate vicinity influences the growth of each droplet as the surrounding vapor field permeates the droplets. The diffusion of water vapor molecules in the humid air and their interaction with the liquid-vapor interface govern the growth of the individual condensate droplets. Nevertheless, most existing numerical models for condensation neglect the effect of neighboring droplets and the vapor concentration field surrounding each droplet. In this study, the point sink superposition method (PSSM) is used to calculate the growth rate of condensing droplets by approximating the inter-droplet interaction and the influences of the surrounding vapor concentration field. Further, this study simulated the condensation process on a vertically oriented hydrophobic surface by capturing condensation dynamics such as coalescence, droplet drainage, and renucleation.