The role of pore size in heat transfer of oscillating liquid flow in metal foam

Dukhan N., Bagel O., Arbak A.

INTERNATIONAL JOURNAL OF THERMAL SCIENCES, vol.145, 2019 (SCI-Expanded) identifier identifier


The huge accessible surface area, high conductivity make metal foam attractive for energy technologies, e.g., reactors, regenerators and Stirling engines. An experiment establishing the impact of pore density of metal foam on heat transfer caused by oscillating water flow through foam is described. Various pertinent parameters for two foams having 10 and 40 pores per inch (ppi), of commercial high-porosity metal foams were obtained in this experiments; and are compared to those of a 20-ppi results from the literature. Experimental runs were conducted at kinetic Reynolds numbers between 1875 and 9366. The wall temperature uniformity and cycleaveraged Nusselt number for the three pore densities were compared to their counterpart for steady-state heat transfer. The pressure drop in the three pore densities was measured and discussed along with the heat transfer results. The effect of pore density was evident in the cycle-average wall temperature and Nusselt number, with the 10-ppi foam outperforming the 20- and 40-ppi foams. The benefit of oscillating flow was seen in producing more uniform wall temperature. It seemed possible for steady-state flow to produce higher heat transfer rates compared to steady-state flow, if the flow displacements were not sufficiently long compared to the length of metal foam.