高导热低泄漏复合相变材料的制备及其热控性能研究

Preparation and Thermal Control Performance of High Thermal Conductivity and Low Leakage Composite Phase Change Materials

相变材料在发生相变时可以在维持自身温度不变的情况下吸收/释放大量热量。将相变材料应用于航天器热控系统中可以有效解决航空设备的温控问题,将设备温度维持在正常工作温度范围内。石蜡作为应用最为广泛的相变材料具有热导率低和相变过程容易泄漏的问题。为了满足航空设备热控需求,采用简单模压及真空浸渍的方法制备了一种高导热低泄漏的石蜡/膨胀石墨复合相变材料。当膨胀石墨泡沫密度为0.5g/cm^(3)时,相变材料热导率为48.7W/m⋅K,比纯石蜡提高了约220倍;其在60°C加热24h的泄漏率仅为0.6%,表现出较好的定型能力;对复合相变材料进行热控实验时,表现出良好的热控性能。

Phase change material can absorb/release a lot of heat and it’s temperature can keep constant in the process of phase transitions.The application of phase change materials in spacecraft thermal control system can ensure the electronic components always working at proper temperature.Paraffin,as one of the most widely used phase change material,has the problems of low thermal conductivity and easy leakage during the phase transitions.In order to meet the requirements of spacecraft thermal control,a kind of paraffin/expanded graphite composite phase change material(CPCM)with high thermal conductivity and low leakage is prepared by simple molding and vacuum impregnation.When the density of expanded graphite foam is 0.5g/cm^(3),the thermal conductivity of the CPCM is 48.7W/m⋅K,which is about 220 times higher than that of pure PW.The leakage rate of the CPCM heated at 60℃for 24 hours is only 0.6%,showing good shaping ability.When the thermal control experiment is carried out on the CPCM,it showes excellent thermal control performance.