Pore-scale simulation of forced convection heat transfer under turbulent conditions in open-cell metal foam

Abstract

Previously, extensive efforts have been made in investigating heat transfer in open-cell metal foams in order to better understand and apply them in engineering applications. As a step in this direction, this study prepared five three-dimensional models of copper foam with various porosities (0.82, 0.87, and 0.90) and pores per inch (PPI) (10, 20, and 40) using X-ray computed tomography and several software applications to simulate forced convection heat transfer in a metal foam at a high velocity. The effects of porosity, PPI, and closed pores on the pressure drop and heat transfer properties were investigated. The results indicated that the pressure drop and heat transfer coefficient were more sensitive to porosity than PPI. However, the specific surface area of the metal foam significantly affected the volumetric heat transfer performance. Additionally, the area goodness factors (j/f) were used to evaluate the comprehensive heat transfer performance (CHTP) of each sample. The value of j/f decreased rapidly in the velocity range of 0–20 m/s but slowly in the range of 20–70 m/s, and sample 40–0.87 exhibited a better CHTP. Moreover, the closed pores in the metal foam had a significant effect on the pressure drop, heat transfer properties, and CHTP due to the obstructions posed by the closed pores. Our work helps provide a better understanding for the application of metal foam in heat transfer enhancement at high velocities.