强制对流下深冷水平平板结霜行为模拟研究

Simulation study on frosting behavior on cryogenic plate under forced convection

基于耦合霜层孔隙率修正的格子Boltzmann方法和扩散抑制凝聚方法,建立了强制对流下深冷表面结霜模型,验证了该模型的可靠性,研究了冷表面温度、空气温度、空气相对湿度及空气流速对深冷表面霜层生长的影响。结果表明:空气流速对深冷表面的霜层形貌影响最大;空气相对湿度和空气速度对强制对流下深冷平板上霜层生长的影响较大;在结霜45 min的情况下,空气相对湿度每提高20%,霜层厚度平均提高11.89%,霜层密度平均增加17.76%;空气速度每提高1 m/s,霜层厚度平均降低8.95%,而霜层密度平均增加14.38%。

A mathematical model coupled improved lattice Boltzmann method and diffusion-limited aggregation method was developed to study frosting behavior of cryogenic plate under forced convection. In order to make the simulation more realistic, the improved lattice Boltzmann method was used by using porosity of frost layer to correct the flow fluid. After the reliability of the mathematical model was verified by the experiment data, the effects of cold surface temperature, air temperature, relative air humidity and air velocity on frost growth were discussed. The impact of above influence factors on frost growth was assessed.The results show that air velocity has the greatest influence on frost morphology, and relative air humidity and air velocity are the main factors affecting the growth of frost layer on the cold plate under forced convection. In the case of frosting for 45 min, the density of frost layer can increase by 11.89%, and the thickness of frost layer can increase by 17.76% on average with 20% decrease of relative air humidity. When the air velocity is raised by 1 m/s, the thickness of frost layer can increase by 8.95%, and the density of frost layer can increase by 14.38% on average.