The heat transfer and pressure drop characteristics of wet air in metal foams with different pore density were experimentally investigated

and the comprehensive performance of metal foam heat exchangers was analyzed. The test sample is copper foam

the PPI value of the tested metal foam covers 5-40 and the porosity is 95%. The results showed that the heat transfer coefficient increased initially and then decreased with the increase of PPI values due to the presence of the condense water. It reached up to the maximum value as the pore density was 15 PPI. The pressure drop increased with increasing pore density and the increment was more obvious as PPI value was higher than 20. The comprehensive performance was the best for the metal foam with 15 PPI by considering both the heat transfer coefficient and pressure drop.