关键词: 有效热导率, 热传导, 泡沫, 预测, 复合材料, 多孔介质, 晶胞分析

Abstract:

As a new type of functional material, open-cell metal foam has developed rapidly in the field of heat and mass transfer in recent years due to its small specific gravity, large specific surface area, high porosity and high thermal conductivity, especially the composite material formed after filling the medium. With its high thermal conductivity, the thermal conductivity of the filling medium was greatly improved. The current research mainly focuses on the flow and heat transfer process, and the systematic research on the effective thermal conductivity was not comprehensive, especially based on the complex three-dimensional structure. And most of the research was also focused on the experimental measurement, there were different gaps in the test conditions and errors. Effective thermal conductivity is an important parameter for the heat transfer and thermal properties of open-cell metal foam composites. Therefore, exploring the effective thermal conductivity and its influencing factors from the structural aspect is one of the ways to solve the problem. Based on the complexity of the three-dimensional structure, starting from the boundary model and the unit cell analysis model, a more comprehensive overview of the current research status of the effective thermal conductivity of open-cell foam metal composites was given. The methods and main models currently used in the research were summarized. It was pointed out that the influence of microscopic pore structure was ignored by the boundary model of macroscopic analysis of heat conduction problems by homogenization method. The empirical correlation analysis method of the cube model and the Kelvin model in the unit cell analysis model were emphasized. Its key point was pointed out that the shape parameters of the porous structure were fitted to the expression of adjustable empirical parameters in the form of porosity. In addition, 3D computed tomography was combined with numerical simulation methods. The research methods of the effective thermal conductivity of the real open-cell foam structure under high-precision calculation were proposed, especially the lattice-Boltzmann method for the study of the open-cell foam structure. The influence and law of the anisotropy of the real pore structure on the effective thermal conductivity were mainly analyzed. For 3D reconstruction numerical analysis, a simplified comparative analysis model needs to be sought to greatly reduce the computational cost. Relying on the existing scientific and technological research methods, the focus of the later research is the accurate fitting method of the empirical correlation model, the unification of the feature correlation, and the simplified comparative analysis model in the high-precision numerical simulation calculation.

Key words: effective thermal conductivity, heat conduction, foam, prediction, composities, porous media, unit cell analysis