Experimental investigation on buoyancy-induced convection in aluminum metal foams

In this work, we studied the thermal performance of aluminum metal foams in buoyancy-induced convection. We investigated the effect of heat transfer performance on metal foam fins heated from below due to the use of different aspect-ratio. The samples used in the trial were characterized by a square base of 50 mm length and seven different heights, which ranged from 10 mm to 150 mm. The samples were made of aluminum metal foam characterized by 5 PPI and a porosity of 0.95. The analysis showed that the heat dissipation increased asymptotically with the height of the sample. The results also showed that the Darcy characteristic length should be not correlated to the sample height. A novel empirical correlation is proposed for the computation of Nusselt number as a function of Rayleigh and Darcy numbers, and a shape function η.