Study on enhanced heat transfer performance of open-cell metal foams based on a hexahedron model

Abstract

Due to its high heat transfer performance, the open-cell metal foam has a great potential of applications in heat exchanger industries. Based on the cell structure of the perforated metal foam, a simplified hexahedral structure model was proposed herein. The fluid flow in metal foams was simulated by computational fluid dynamics software. The accuracy of the model was verified by experiments. Based on the numerical simulation, heat transfer performance and the mechanism of enhanced heat transfer were investigated and discussed. The results show that the hexahedron model proposed in this article is feasible and accurate. The heat transfer and pressure drop properties of metal foams were numerically calculated and analyzed at the inlet air velocity of 1–5 m/s. At a certain PPI (pores per inch) and porosity, with the increase of Reynolds number Re, both the heat transfer coefficient h and pressure drop ΔP/L increase gradually. The comprehensive performance of convective heat transfer of metal foams with a lower PPI is relatively better. Increasing PPI or decreasing porosity is conducive to the destruction of the fluid boundary layer, enhancing the fluid disturbance, thus forming a vortex at the back of the skeleton and strengthening the heat transfer.