Experimental Investigation on Mixed Convection in Horizontal Channels Heated Below and Partially Filled With Aluminum Foam

Abstract

In this paper an experimental investigation on mixed convection in air in a heated channel partially filled with an aluminum foam is carried out. The aluminum foam layer is sets on the lower heated wall of the channel. The channel upper plate has a heat transfer toward the external ambient. The investigation allows to evaluate the effect of the aluminum foam on the mixed convection in the heated channel by wall temperature measurements and flow visualization. Results are given for heated channel without and with foam in terms of wall temperature profiles for different Reynolds number value, form 10 to 300, wall heat flux and for aluminum foam with 10 and 20 pore per inch. Lower wall temperature values are detected for the channel with foam with respect to the channel clean without foam. Foams with higher pore per inch shows lower average wall temperature values whereas the local wall temperatures showed different behaviors for the different pore per inch values. The presence of foam in heated channel determined weaker secondary motions with respect to the clean cases. The effect of the foams seems more significant for the high Reynolds number values and average Nusselt number increases with the foam presence in the heated channel.