Numerical Analysis of Air Flow through Metal Foams

X-ray micro computed tomography (μ-CT), originally developed for non-destructive biomedical imaging, is increasingly being employed in areas as diverse as materials characterization and reverse engineering. The technique employs computer processed X-rays to produce tomographic images or slices of specific regions of the object under investigation. This paper presents a numerical analysis of air flow through four different high-porosity ERG copper foams having different pore sizes (5, 10, 20, and 40 pores per inch, PPI), and approximately the same relative density (6.4-6.6% solid fraction). These samples were scanned with a commercial micro computed tomography scanner at a resolution of 20 μm, yielding a stack of two-imensional images. Starting with these two-dimensional images, the real, random structure of the foams was reconstructed and subsequently meshed using the commercial software Simpleware. Meshes thus produced were then exported to FLUENT for simulating the fluid flow through the pore space of the foam samples. The results of μ-CT based CFD computations are compared against experimental measurements of pressure drop that were previously obtained with the same samples. The comparison reveals excellent agreement between the numerical and experimental results, highlighting the accuracy of this novel approach.