Transient thermal performance enhancement of phase change material (RT82) through novel pin arrangements under varied gravity conditions

Phase change materials (PCMs) are an effective medium for thermal management of avionics because of their ability to absorb, store, and release high heat loads while operating within narrow temperature range in confined spaces. Despite hosting several benefits, PCM systems suffer from low thermal conductivity issue. Strategically placed fins in a volume filled with PCM has the potential to significantly improve the transient thermal performance of PCMs by improving the overall thermal conductivity and providing enhanced heat transfer surface area. Furthermore, avionics can be subjected to varying gravity conditions during flight that can have significant influence on the overall thermal performance of PCMs. This emphasizes the need to characterize the PCM performance under various gravity conditions that can impart different buoyancy induced effects in a confined system. To this end, numerical investigation to study the melting characteristics of PCM-fin configuration subjected to three different gravity conditions, i.e., (a) microgravity, (b) terrestrial gravity, and (c) hypergravity, is conducted. The influence of these three conditions on the performance of PCM-fin combination configuration is investigated and finally the temperature field, melt fraction, and melting time is reported. The performance of PCM-fin system is compared with the corresponding PCM-only configuration to highlight the benefits of adding fins under each investigated gravity condition.