Numerical study of flow and heat transfer in the air-side metal foam partially filled channels of panel-type radiator under forced convection

To improve heat dissipation performance of panel-type radiator for transformers, this study investigated the flow and heat transfer characteristics in the air-side metal foam partially filled channels of the radiator. The porous thin-layer filled (PTLF) and porous fin filled (PFF) methods and the filling ratio (V p) were analyzed and compared. The result indicated that the permeability and interfacial turbulent kinetic energy in the porous region of PFF channel are higher. Increasing V p can promote flow mixing and heat transfer. For Re = 5,125-15,375, when V p = 11.1%, the performance evaluation criterion in PFF channel can increase by 12.0-30.8% as compared with PTLF channel. Then, the effects of metal foam material, porosity (phi), and pore density (omega) were explored. The results show that decreasing phi, increasing omega, and using copper metal foam are all beneficial for enhancing the heat transfer performance of the PFF channel within the range studied. Finally, when V p = 11.1%, the PFF channels filled with Cu-10-9.5 and Al-10-9.7 samples were selected for comparison with previous related studies, which demonstrated the feasibility of the metal foam partial filling method on the air side of the panel-type radiator.