Abstract

Dropwise condensation on rough surfaces enhanced with pillars in the presence of non-condensable gas (NCG) including the initial nucleation process is simulated using the multispecies multiphase lattice Boltzmann method, and the effect of mass fraction of NCG, the surface wettability, the bottom wall temperature and the geometrical parameter (the pillar height H) on condensation process are investigated. It's found that these four factors all have an effect on the nucleation position, waiting time, condensate behaviors, and the wetting state of the droplet. With higher values of NCG mass fraction, surface hydrophobicity, pillar height H, and lower bottom wall temperature, the nucleation occurs on top of the pillars and the waiting time before nucleation gets longer. It's also concluded that the wetting state of the droplet tends to be the Cassie state, and the average heat flux gets smaller with higher values of the former three parameters and lower bottom wall temperature.

摘要

使用多物种多相格子Boltzmann方法模拟了在存在不凝性气体（NCG）的情况下使用支柱增强的粗糙表面上的逐滴凝结，包括多晶种多相晶格Boltzmann方法，以及NCG的质量分数，表面润湿性，底壁的影响研究了凝结过程中的温度和几何参数（立柱高度H）。发现这四个因素都对成核位置，等待时间，冷凝行为和液滴的润湿状态有影响。随着较高的NCG质量分数，表面疏水性，柱高H和较低的底壁温度，成核发生在柱的顶部，并且成核的等待时间变长。它'