Heat transfer characteristics of aluminum foam heat sinks subject to an impinging jet under fixed pumping power

Abstract

In this study, the heat transfer characteristics of an aluminum foam heat sink subject to an impinging air jet is investigated experimentally, under fixed pumping power condition. The effects of dimensionless pumping power, Reynolds number and the dimensionless impinging distance on the Nusselt number are considered. The result shows that the effect of the impinging distance on the Nusselt number is negligible under fixed Reynolds number, while the Nusselt number decreases with decreasing impinging distance under fixed pumping power. Based on the experimental results, an empirical correlation for predicting the Nusselt number is suggested as a function of the dimensionless pumping power and dimensionless impinging distance. The foam heat sink is shown to have better thermal performance than pin fin heat sink with same porosity under impingement cooling, when the Reynolds number is low. The trend is reversed for larger Reynolds number. The effect of cross sectional shape of jet impingement on the Nusselt number is shown to be insignificant.