Experimental study on liquid drainage characteristics of metal foams under sloshing conditions
Abstract For applying metal foam in enhancing the condensation heat transfer of shell-and-tube heat exchangers, the liquid drainage characteristics of metal foams under sloshing conditions are investigated experimentally. The experimental conditions include the pore density of 5-40 PPI and the porosity of 0.85–0.95. The results show that, the liquid drainage performance of metal foams is improved by sloshing motions; as the sloshing frequency and angle increase, the liquid retention of metal foam decreases by a maximum of 44%. A sloshing impact factor is employed to evaluate the influence of sloshing motions, and the impact factors of rolling, swaying and heaving motions are within 0.56–1.0, 0.93–1.0 and 0.92–1.0, respectively. With the increasing PPI, the shape of liquid retained in metal foam changes from droplet to scattered or full layer, which has significant effect on the drainage performance. A correlation for predicting the mass liquid retention was developed within a deviation of ±20%.