ANALYSIS OF PLATE-FIN HEAT SINK INFUSED WITH PHASE CHANGE MATERIALS FOR INTERMITTENT SPACE MISSIONS

Abstract

In this work, we numerically investigated the heat transfer effectiveness of different phase change materials (PCMs) when infused in a plate-fin heat sink with a fixed volume fraction of thermal conductivity enhancer. The PCM's ability to absorb and release large amounts of thermal energy at constant temperature is a desired feature in transient electronics cooling applications. In this study, we focused on examining the effect of the number of fins, type of PCM, heat flux, PCM volume fraction, and heat sink bottom wall thickness. The results showed that increasing the number of fins improved the performance of the PCM-infused heat sink. When a heat flux of 4000 W/m<sup>2</sup> was applied for 30 minutes on a plate-fin heat sink infused with paraffin wax, the maximum temperature did not exceed 70°C in the four-fin design, while it exceeded 80°C in the two-fin design. A salt hydrate PCM outperformed paraffin wax and RT35. The bottom wall of the heat sink acted as a thermal spreader and a nonlinear relationship existed between the bottom wall thickness and the maximum electronics temperature. Compared to the two- and four-fin heat sink models, the zero-fin model required the longest time to fully melt the entire PCM due to the additional amount of PCM present in the heat sink gaps.