Experimental investigation on local heat transfer analysis of heated surface embedded with metal foam using circular orifice air-jet impingement

Abstract

The use of metal foam in conjunction with air-jet impingement enhances heat transfer in electronic cooling systems by expanding convection surface area, improving heat dissipation, and enhancing coolant mixing. It may reduce concentrated heat flow and improve cooling efficiency in sectors like electronics, aerospace, and automotive. The present study examines the heat transfer attributes of a heated surface combined with metal foam and exposed to an air jet, revealing its potential for improving cooling systems. This study conducts an experimental analysis to assess the impact of a circular orifice on the thermal transfer characteristics of a metal foamed surface. Present research examines many characteristics, including nozzle-to-plate distance (z/d) and local and average heat transfer (Nusselt number), both along the longitudinal and transverse axes at varying Reynolds numbers (Re = 10000–50000) and plate-to-nozzle distances (z/d = 2–10) using infrared images obtained by the thin foil thermal imaging technique. The emphasis of the study is on the local distribution of these heat transfer characteristics. A copper metal foam with a porosity of 90 % and 20 pores per inch is combined with the flat plate. When compared to foil without foam, the thermal properties of heated thin foil integrated with metal foam using a circular orifice are found to be better in the stagnation region. Moreover, this study also investigates the influence of plate segments integrated with metal foam on the distribution of localized and average heat transfer. The thermal performance of the thin foil, when paired with the metal foam in the stagnation zone, is superior to that of the foil without foam. The local Nusselt number for y/d = 0, 2, 4 and 6 with foam at the stagnation point (x/d = 0) increases by 112 %, 107 %, 129 %, and 124 %, accordingly, as the Re increases from 10000 to 50000. The use of an integrated metal foam heated plate enhances localized thermal propagation. The foam effect is more evident in the impingement zone than in the wall jet region at a lower z/d. At lower impinging distances, foam at the impingement zone contributes more to heat transmission and results in non-uniform cooling. Higher impinging distances approaching z/d = 6–8 may result in consistent cooling and optimal foam use. © 2025 Elsevier Ltd