Hydraulic and thermal performances of metal foam and pin fin hybrid heat sink

In this study, a metal foam and pin fin hybrid heat sink (MFPFH heat sink) is proposed for thermal management of high powered electronic devices. Thermo-hydraulic performance of MFPFH heat sink is numerically investigated under local thermal non-equilibrium condition, and compared with metal foam (MF) heat sink and traditional pin fin (PF) heat sink. Influences of MF morphological parameters on flow and heat transfer of MFPFH heat sink are analyzed, and the thermal performance ratio is evaluated. Thermal contact resistance between PFs and MF is introduced to explain its effects on the thermal performance of MFPFH heat sink for its practical application. Results indicate that significant heat transfer enhancement is achieved by using the MFPFH heat sink, due to the enhanced heat conduction and the improved heat convection by the common contribution of MF and PFs. Heat transfer characteristics of MFPFH heat sink are more sensitive to foam porosity, and pressure drop to pore size. By simultaneously considering the heat transfer enhancement and flow resistance increase, the thermal performance ratio of MFPFH heat sink is 1.6 times higher than the traditional PF heat sink. When thermal contact resistance is 10(-3) m(2).K/W, the degradation of average Nusselt number is approximately 36%.