Numerical Analysis of Liquid Jet Impingement through Confined Uniform Cooling Channels Employing Porous Metal Foams

Abstract

In this study, liquid jet impingement through porous metal foam-filled cooling channels with uniform cross sections and subject to a high heat flux value of 10⁵ W/m² is investigated numerically and several effective parameters are studied to achieve highly effective thermal control designs. The studied metal foam substrates are porous structures made of copper with porosity values of 0.45 and 0.86, and aluminum with the porosity value of 0.88. Three different jet inlet cross section shapes of rectangular slot, square, and circular are utilized in this work, while the jet flow rate for all cases is kept the same. To investigate the effect of jet size, three different circular jet diameters are modeled; one providing the same hydraulic diameter as that of the square jet, one indicating the same cross section area as that of the square case, and one representing a smaller jet cross section size. In addition, the effects of jet-to-target spacing and utilization of combined metal foam and conductive fins are studied. The comparisons are performed in terms of pressure drop, required pumping power, and nondimensional temperature profile and contour. The results indicate the advantage of utilizing copper foam with 0.86 porosity and circular jet impingement. Also, the local temperature can considerably be reduced when the combined foam and fin design is utilized. For hotspot treatment using combined foam and fin structure, the fin should be placed at the hotspot zone, right in front of the impinging jet. Among the studied fin-structured cases, the cross-shaped fin provides the most effective cooling without additional required pumping power.