Enhanced heat transfer of PCM-based heat sink augmented with plate-fins and hybrid nanoparticles for electronics cooling

Passive cooling technologies based on phase change material (PCM) reveal as emerging technique for thermal management of electronic components efficiently. Therefore, the current study explores the combined effect of hybrid nanoparticles (HNPs), plate-fins, and PCM integrated in a heat sink for both heating and cooling operation modes. As, PCM exhibits the lower thermal conductivity which makes it unfavourable for rapid heat transfer modes especially while solidification phase. Therefore, the novel incorporation of higher thermal conductive fins and hybrid nanoparticles with PCM are numerically studied to promote the heat transfer rate while melting and solidification phases. HNPs of graphene nanoplatelets (GNP)-copper (Cu) are dispersed in PCM of varying loading content (2%$\le$ $\phi$ $\le$6%) to develop hybrid nanocomposite phase change material (HNcPCM). Similarly, the number of plate-fins are varied by changing their volume fraction (0%$\le$ $\gamma$ $\le$20%). Under a constant heat flux, the thermal performance is evaluated under transient conditions for both qualitative and quantitative aspects. Results exhibit the rapid enhancement in heat transfer rate during melting/solidification and a lower heat sink base temperature is revealed. A reduction in heat sink base temperature is reduced by 4.0% and 5.35% with 10% and 20%, respectively, compared to 0% without HNPs. However, this reduction is achieved of 0.63%, 1.10% and 1.5% with 2%, 4% and 6% of $\phi$ hybrid nanoparticles, respectively, with 10% compared to 0%. The heat storage/release capacity ($Q$) and heat storage/release density ($q$) exhibit the decreasing trend because of increase in total mass of HNcPCM-Fins. A reduction in $Q$ and $q$ is obtained of 24.18% and 23.1%, respectively, for 10% during melting phase in latent-heat state. The addition of plate-fins and GNP-Cu HNPs present a uniform melting/solidification phenomenon of HNcPCM inside the heat sink and a rapid melting/solidification rate and phase completion time are obtained, which understands the fluctuating operating modes. The higher enhancement in temperature response rate is obtained in case of plate-fins compared to the addition of GNP-Cu HNPs for both melting and solidification phases. The enhancement in heat transfer ($\acute{Q}$) and heat transfer density (q́) is obtained of 12.23% and 13.84% for 10%, respectively, during cooling phase compared to 0% in latent-heat state. The optimum volume fractions of GNP-Cu HNPs and plate-fins are found of 2% and 10%, respectively, for effective thermal management performance of a HNcPCM-Finned integrated heat sink system.