基于硬脂酸复合相变材料的被动热沉性能

固液相变储能材料的被动热沉广泛应用于航空航天及军事装备领域。针对高热流密度电子芯片的被动温控问题，对比实验验证了单温度和双温度2种数值模拟方法对基于泡沫铜/硬脂酸复合相变材料被动热沉控温过程模拟的准确性。结合基于Maxwell-Garnett模型的EMT建立了石墨烯纳米片/硬脂酸复合相变材料物性，采用更为精确的双温度数值模拟方法分析了不同导热强化方式的控温效果，并研究了环境温度对热沉控温效果的影响。结果表明:高热流密度下的相变温控过程采用双温度数值模拟更为精确；当导热增强体的体积组分相同时，提高泡沫金属的孔密度对相变温控效果提升有限，而同时采用泡沫金属与石墨烯纳米片能更有效改善相变控温效果；环境温度的剧烈变化对温控时间和控温温度均能产生影响。 

Performance of a passive heat sink using stearic acid based composite as phase change material

The phase change material based passive heat sink is widely applied in the fields of aerospace and military equipment. To address the thermal management of electronic chip with high heat flux, the single temperature energy equation and the two temperature energy equation were applied to simulate the thermal management performance of the copper foam/stearic acid based heat sink, and their accuracy were validated by the lab-scale experiment. By combining with the thermal properties of grapheme nanoplatelets/stearic acid composite phase change material established by EMT based on Maxwell-Garnett model, the influence of different composition of thermal conductivity enhancement on the thermal performance of the heat sink was investigated. And the effect of the ambient temperature was studied. The results show that the two temperature energy equations can simulate more accurately when the heat flux of the chip is higher. When the volume fraction of the thermal conductivity enhancer is fixed, increasing pore density of copper foam has few improvement on the thermal management performance, while copper foam with GnP can effectively improve the thermal management performance of the heat sink. The serious change of ambient temperature can play an important role in the managed temperature and temperature control time.