Pore-scale numerical study of flow characteristics in anisotropic metal foam with actual skeleton structure

Owing to the complex structure of open-cell metal foams, skeleton structures that do not include micropores have been widely used to represent foam structures in recent years. In this study, three-dimensional metal foam structures with and without skeleton micropores were reconstructed by combining the use of a micron X-ray three-dimensional imaging machine and ImageJ and Mimics Research software. The anisotropic flow characteristics of the two structures at velocities ranging from 0.5 m/s to 2.5 m/s were investigated. The results indicate that the pressure drop in the structure with skeleton micropores is 11.3–11.7% higher than that in the structure without skeleton micropores. The flow characteristics in the three orthogonal Cartesian axes exhibit obvious anisotropy, while they are not distinguishable in opposite directions along the same axis. The pressure drop in the Y-direction is the highest among the three axis directions, and is 31.6–32.8% higher than that in the Z-direction for the structure without skeleton micropores, and 35.4–36.8% higher than that in the Z-direction for the structure with skeleton micropores. The above findings indicate that the effects of skeleton micropores and the anisotropic characteristics of the metal foam on the flow characteristics in actual metal foam should be considered.