Local Heat Transfer Distribution in Channel Flow Through a Periodic Octet Foam with Separation of Fin and Wall Heat Transfer

This study investigates local heat transfer distribution and pressure drop in octet-structured aluminium foam (AlSi10Mg) within a rectangular channel. The local heat transfer distribution is analysed using a thin metal foil technique and an IR camera. The foam has a thickness of 12.5 mm and 70.6 % porosity. Experiments were performed to study the effect of Reynolds numbers on heat transfer performance and assess the contribution of conductive versus convective heat transfer. A range of Reynolds numbers were tested from 1000 to 25000. The heat transfer coefficient asymptotes to a constant value beyond the Reynolds number of 20000. To segregate the effect of fin and wall heat transfer, separate experiments are conducted using resin foam. The effect of conduction heat transfer (fin) dominates convection heat transfer (wall), with a contribution ratio of 81-19 %. Metal foam exhibits a 3.5-5 times higher heat transfer coefficient than resin foam. The performance enhancement over smooth channels is 5 times higher for resin foam and 18 to 29 times higher for metal foam. The Performance Evaluation Criterion for metal foam ranges from 2.02 to 3.11, while for resin foam, Performance Evaluation Criterion is between 0.56 and 0.63. The Constant Pumping Power Criterion shows a 32 % higher thermal performance than the Performance Evaluation Criterion.