Analyzing the melting process in a tilted heat sink filled with a phase change material equipped with the plate and optimized tree-shaped metal fins

The prevalent practice of integrating metal fins into phase change material (PCM) serves to enhance the thermal conductivity of PCM technology, which finds extensive utility in the efficient heat management of electronic devices. This study delves into the thermal behavior of an inclined heat sink that employs both the optimized tree-shaped and plate fins, each with volume fractions of 20 % and 30 %. The tree-shaped fins underwent optimization using the density-driven topology optimization technique. The heat sinks are loaded with either pure PCM or various types of nano-enhanced PCMs. The study highlights the superior performance of tree-shaped fins in terms of promoting temperature uniformity across the heat sink. It is also found that the performance of tree-shaped and plate designs of metal fins in achieving lower melting times is dependent on the inclination angle of the device. The plate heat sink with a metal volume fraction of 20 % and tree-shaped heat sink with a metal volume fraction of 30 % exhibit, respectively, the highest and the least dependence on the inclination angle in terms of its thermal behavior. Moreover, both the plate and tree-shaped heat sinks demonstrate the quickest complete melting time when the inclination angle is set to 0°. In the tree-shaped heat sink with 20 % and 30 % mass fractions, PCM experiences the longest complete melting time at inclination angles of 75° and 90°, respectively. Furthermore, the most significant reduction in melting time for tree-shaped heat sinks with 20 % and 30 % mass fractions, compared to plate heat sinks, is observed at inclined angles of 30° and 45°. Furthermore, the investigation shows that plate-fin heat sinks experience a more significant enhancement in melting rate due to the presence of diverse nanoparticles. Also, the dispersion of various nano-additives in the PCM within the plate-fin heat sink with a metal mass fraction of 30 % leads to a notable reduction in the maximum temperature of the concentrated heat source (approximately 6.5^°C). In contrast, the addition of nano-additives does not have a substantial effect on the maximum temperature for the optimized tree-shaped heat sinks. Finally, upon loading the nanoparticles into the PCM, the plate-fin heat sink with a metal mass fraction of 20 % exhibits the highest temperature non-uniformity within the metal structure, while the tree-shaped heat sink with a metal mass fraction of 30 % shows the lowest.