Experimental Investigation on Confined Jet Impingement Boiling Heat Transfer Characteristics on Metal Foam Cover

Metal foam has great potential for promoting boiling heat transfer due to its complex porous structure and extraordinarily large specific surface area. The boiling heat transfer characteristics of confined single jet impingement on a metal foam covered surface were experimentally investigated for the first time, and the new data were compared with those on the smooth surface. The experimental results show that, the heat transfer performance of metal foam is affected by jet velocity and subcooled degree in the nucleate boiling region due to the significant contribution of single-phase convection heat transfer; critical heat flux of the metal foam covered surface is 10 %-36 % higher than that of the smooth surface, representing a maximal of 206.7 W center dot cm(-2); the highest heat transfer coefficient is up to 39.9 kW center dot m(-2)center dot K-1, 31 % greater than that of the smooth surface; at the same surface superheated degree, the heat flux of the metal foam covered surface is 9 %-166 % greater than that of the smooth surface; at the same heat flux, the heat transfer coefficient on the metal foam covered surface is 14 %-90 % higher than that of the smooth surface; the metal foam cover reduces surface superheated degree by up to 16.8 K at the onset of nucleate boiling.