Characterization of High Porosity Open-Celled Metal Foam Using Computed Tomography Available to Purchase

High porosity metal foams have been the subject of many investigations for use in heat transfer enhancement through increased effective thermal conductivity and surface area. Convection heat transfer applications with these foams have been investigated for a large range of Reynolds numbers. Common to these analyses is the need for quantitative information about the interfacial surface area and the effective thermal conductivity of the metal foam. The effective thermal conductivity of these metal foams have been well characterized, however little investigation has been made into the actual surface area of the foam and its dependence on the foam pore density and porosity. Three-dimensional x-ray computed tomography (CT) is used for determining interfacial surface area and ligament diameter of metal foam with porosities ranging from 0.85 to 0.97 and pore densities of 5, 10, 20, and 40 pores per inch. Calibration samples with known surface area and volume are utilized to benchmark the CT process. Foam results are compared to analytical results obtained from the development of a three-dimensional model of the high porosity open-celled foam. The results obtained are compared to results from previous investigations into these geometric parameters. Results from calibration sample comparison and analysis of the foam indicate the need for additional work in quantifying the repeatability and sources of error in CT measurement process.