Thermal performance of pin fin heat sinks with phase change material for electronic devices thermal management

In the present paper, an experimental and numerical study is conducted to analyze various factors affecting the thermal performance of a heat sink with phase change material (HS-PCM). In order to maintain the chip below the limit temperature of 80 °C, ZDJN-35 with a phase change temperature of 37 ∼ 45 °C is selected as the energy storage material. Under different PCM filling volume fractions, heat fluxes, and operation modes, the study evaluates the thermal performance of the HS using chip temperature and the effective time extension coefficient. The volume fractions of PCM are 0 vol%, 30 vol%, 60 vol%, and 90 vol%. Under heat fluxes of 4000 ∼ 14000 W/m², the results indicate that under continuous operation, the HS without PCM reaches the limit temperature within 18 min at heat flux of 8000 W/m². In contrast, the time to reach the limit temperature for HS with 30 vol% PCM, 60 vol% PCM, and 90 vol% PCM extends by 12 min, 19 min, and 26 min, respectively. Compared to the HS without PCM, the peak temperatures reduce by 4.8 %, 10.5 %, and 12.8 % for the HS with 30 vol% PCM, 60 vol% PCM, and 90 vol% PCM under intermittent operation. Moreover, under intermittent operation, temperature fluctuations decrease by 27.3 %, 36.0 %, and 37.3 %, respectively. Finally, the numerical results show that the optimization of pin fin diameter is opposite for passive and active cooling modes, and a heat dissipation unit height of 25.5 mm is recommended.