Convection heat transfer from aluminium and copper foams in a vertical channel – An experimental study

Abstract

This paper reports the effect of thickness and thermal conductivity of high porosity foams on heat transfer and pressure drop in a vertical channel for an inlet velocity range of 0.4–3 m/s. Hydrodynamic and heat transfer experiments are conducted in a vertical wind tunnel, containing symmetrically heated aluminium and copper foams of 10 mm, 20 mm and 30 mm thickness and porosity of 0.95 and 0.87 respectively on either side of the plate heater, with air as the cooling fluid. The novelty of the present study is the use of metal foams in a vertical channel without any permanent joint like brazing and the quantification of the heat transfer enhancement compared to an empty channel for different foam thicknesses. This scenario represents the least performance of metal foams. The results of the experiments show that the foam thickness contributes to a significant increase in heat transfer. The pressure drop is insensitive to the foam thickness. Counterintuitively, the effect of higher thermal conductivity of copper foams on heat transfer is not found to be significant for the range of velocities investigated, compared to the case of aluminium foams. Copper foams of porosity of 0.87 and aluminium foams of porosity 0.95 gave the same heat transfer performance for the same velocity range and heat flux conditions.