The Simplified Analytical Models for Evaluating the Heat Transfer Performance of High-Porosity Metal Foams

The accurate evaluation of the specific surface area and the effective thermal conductivity (ETC) of high-porosity metal foams is an important prerequisite to study the mechanism of heat transfer enhancement. In this paper, the tetrakaidecahedron, concave triangular prism and equivalent tetrahedron were used to develop the geometry shapes of cell, ligament and node, respectively. The calculation model of the specific surface area characterized by porosity and pore density (PPI) was deduced by considering the shape characteristics. Based on the angle between the two-dimensional plane skeleton layer and the heat flow direction, the ETC analytical calculation model characterized by only the porosity in the three-dimensional space was deduced. Without any other fitting or experimental empirical parameters, these two models are only related to porosity and PPI, which are the most readily available parameters for the metal foams. The results of these models are consistent with the experimental and empirical data in other literature, indicating that these models are both versatile and accurate.