An Improved Enthalpy-Based Lattice Boltzmann 3D Model with Added Probability Function for the Growth Characteristics of Frost Layer
基于加入概率函数的改进格子 Boltzmann 三维焓法模型的霜层生长特性数值研究
CUI Jing, YANG Tinghao, YANG Fan, YANG Guangfeng
Keywords: lattice Boltzmann model, improved enthalpy model, nucleation probability model, three-dimensional, frost, surface wettability
Journal of Thermal Science, 2019, 28(2): 378-392
本文从介观尺度运用格子Boltzmann 方法数值研究了不同表面特性对霜层生长的影响。将改进的焓法模型和成核概率模型相结合，建立了基于成核概率理论的霜层生长过程的三维格子 Boltzmann 模型，应用此模型开展了冷壁面上霜层形成及生长过程的数值研究发现：该模型既能够从宏观尺度上模拟霜层生长的逐渐变密变厚过程，也可以从微观尺度上描述冰枝生长导致的霜层结构的变化过程，该模型还能够求得霜层平均厚度、平均密度、结霜量等内部非稳态物理量，获得了霜层的拓扑结构时空演化特性。应用此模型分析了冷壁面温度、相对湿度、冷表面浸润性对结霜特性的影响，并通过计算得到了不同影响因素下，不同时刻的霜层的平均厚度、平均密度、结霜量以及平均固相体积分数。
In this paper, the effects of different surface properties on the growth of frost layer were numerically studied from the mesoscopic scale using the lattice Boltzmann method. The improved enthalpy method and nucleation probability model were combined to establish a three-dimensional lattice Boltzmann model based on nucleation probability theory. The model was used to carry out numerical research on frost layer formation and growth process on cold wall surface. The model could not only simulate the gradual densification and thickening process of frost layer growth from the macro scale, but also describe the change process of the frost layer structure caused by ice branch growth on the micro scale. The average thickness, average density and the amount of the frost layer could be obtained. Through this model, the temporal and spatial evolution characteristics of the topography of the frost layer were obtained. The model was used to analyze the effects of cold wall surface temperature, relative humidity and cold surface wettability on the frosting characteristics. The average thickness, frost average density, frost quality and average solid volume fraction of frost at different times were obtained by calculation.