霜晶生长的界面演变及机制分析

Theoretical analysis of interface transformation during frost crystal growth

为了认识冷面结霜的微观机制,对霜晶生长过程中的各种界面演变现象进行了研究。从晶体生长角度解释了各种形状初始霜晶的形成机制;利用界面稳定性理论分析指出:温度场和水蒸气浓度场是影响霜晶生长的主要因素,两者的竞争耦合作用是产生相变和霜晶各种界面演变现象的根本原因;建立了霜晶生长速率与霜晶表面温度及水蒸气分压力相关的数学模型。计算结果表明:随着霜晶温度的降低或环境空气水蒸气分压力的增加,霜晶生长速率增大,这与实验以及基于分子运动论的分析结论是一致的。

The interface transformation phenomena occurring during the growth of frost crystals were studied for better understanding the mechanism of frost formation on cold surfaces. The formation mechanisms of different initial frost crystal shapes were explained from a crystal growth point of view. An interface stability theoretical analysis shows that the temperature field and water vapor concentration field are the main factors affecting frost crystal growth, with the competing and coupling effects of the two fields was the fundamental reason for the phase change and interface transformation phenomena in frost crystals. A mathematical model was then developed to analyze the frost crystal growth rate. The results shows that the frost crystal growth rate increases with decreasing frost crystal temperature or increasing water vapor partial pressure, witch is consistent with experimental results and analyses based on molecular dynamics.