滴状凝结全过程液滴尺寸分布数值模拟

Numerical Simulation of Droplet Size Distribution in the Whole Process of Dropwise Condensation

研究液滴在冷凝表面的尺寸分布特征,不仅有助于了解冷凝表面换热机理,同时也为疏水表面的设计提供参考依据。本研究中,借助于液滴生长、合并和脱落全过程的数值模拟方法,研究液滴凝结核密度和液滴脱落尺寸对液滴尺寸分布的影响。模拟中采用热阻模型对液滴生长进行描述,利用链表搜索算法加速液滴聚合及新凝结核确定的搜索过程,再现大液滴脱落和表面清扫过程。模拟结果与实验结果及理论模型吻合良好。模拟结果表明,随着凝结核密度增大,小液滴数密度相对增加,液滴平均半径减少;随着液滴脱离半径减小,液滴尺寸范围减小,液滴尺寸分布整体升高。

Studying droplet size distribution on the condensation surface not only understands the heat transfer mechanism on the condensation surface,but also provides the reference for the design of the hydrophobic surface.In this paper,the effects of condensation nucleation density and droplet removal size on droplet size distribution were studied by numerical simulation for the whole process of droplet growth,coalescence and removal.In the simulation,the thermal resistance model was used to describe the droplet growth.The linked-list algorithm accelerated the searching in droplet coalescence and re-nucleation.Large droplet removal and surface cleaning were presented.The simulation results were in good agreement with the experimental results and theoretical model.The results showed that the increasing of nucleation density leaded to the increasing of small droplet density and decreasing of droplet average radius and smaller droplet removal size resulted in narrower droplet size range and lower droplet size distribution.