Thermal management of single and multiple PCMs based heat sinks for electronics cooling

The present study focuses on passive thermal management of electronic devices using heat sinks embedded with single or multiple phase change materials (PCMs). RT58, RT44 and n-Eicosane are used as PCMs, while aluminium fins are used as thermal conductivity enhancer (TCE). Single PCM cases are investigated independently while multiple PCMs pairs are studied through their filling in alternate enclosures separately. Three constant heat fluxes of 1.5, 2.5 and 3.5 kW/m2 are applied to the heat sinks to investigate PCMs’ thermal performance. The numerical model is validated against available experimental results where an acceptable 2.9% difference in the transient temperature is achieved. High values of Nusselt number were discovered at the beginning of melting and the end of solidification stages. The RT44 shows the lowest peak temperature and longest melting duration among single PCM cases, due to its high latent heat of fusion. When n-Eicosane and RT44 are paired in a heat sink, the best overall thermal performance is achieved where its operational time is increased by 3.3–12% comparing to single n-Eicosane or RT44. The results show that the multiple PCMs pair of n-Eicosane/RT44 is feasible for high critical temperature devices due to its longer operating time and also lowest average transient temperature.