Enhancing the performance of aluminum foam heat sinks through integrated pin fins

In this paper, the fluid flow and heat transfer performances of aluminum foam heat sink with pin fins (AFPF heat sink) are experimentally and numerically investigated. High porosity aluminum foams with the porosity of 0.88 and pore densities of 10 PPI and 20 PPI are incorporated into the pin fin array channel to form the test sections. The channel consists of five rows of 5 mm x 5 mm square cross-section staggered pin fins with height of 13 mm. The AFPF heat sinks are subjected to the steady water flow covering the Darcy-Forchheimer regime, and measurements of the flow and heat transfer are performed and compared with the aluminum foam (AF) heat sinks. The results show that the insertion of pin fins into the AF heat sink has significant effects on both flow and heat transfer characteristics. Heat transfer performance of AFPF and AF heat sinks both increases with increasing pore density. The improvement of average Nusselt number in AFPF heat sink of 20 PPI is approximately 63.5-68.1% compared to the AF heat sink, while the deduced flow resistance is increased by 49.2-88.1%. The thermal performance of the AFPF heat sink is found to be 1.5 times of the AF heat sink under a given pumping power. In addition, a numerical model capable of predicting the temperature distribution and pressure drop is developed and experimentally validated. (C) 2020 Elsevier Ltd. All rights reserved.