Numerical simulation and experimental study on the thermal characteristics of composite phase change materials for heat storage
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摘要: 复合相变材料(PCM)作为一种固/液相变材料与多孔高导热泡沫等材料复合而成的新型材料体系,具有潜热大和热导率高等优异性能。因此,基于复合相变材料的蓄热装置成为新一代飞行器热管理技术的研究热点。以碳化硅(SiC)泡沫填充石蜡类相变材料为研究对象,采用有限容积法与等效热容法相结合的方法,建立了考虑材料细观与宏观传热特性的复合相变材料传热特性数值预测方法,搭建了实验平台并开展了材料传热特性的实验研究,验证了计算模型与方法的有效性。相关方法可为材料孔隙率、微结构等特征对复合相变材料传热特性的影响规律研究以及材料蓄热性能的优化提供参考。Abstract: The composite phase change material (PCM) is a new type of phase change material with the high porosity foam as a thermal conductivity enhancer. It has lots of excellent performances including large amount of latent heat and higher thermal conductivity than pure PCM, which make the device with composite PCM for heat storage to be an efficient thermal management technique for the next generation aircraft. The thermal characteristics of SiC foam filled paraffin waxes were studied in this paper. To simulate the heat transfer of composite PCM, a finite volume technique was used to discretize the heat diffusion equation, and the two-temperature model was employed for the small scale material while the equivalent specific heat method was used for the large scale material. The experimental setup was build up and heat transfer experiments were performed to validate the proposed numerical method. The experimental and numerical results show good agreement, which indicates the effectiveness of the proposed numerical model in this work. Based on the numerical method, the effects of the porosity on the equivalent thermal conductivity, and the effects of the microstructure on the equivalent thermal conductivity could be studied in further work.
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表 1 复合相变材料热物性参数
Table 1. Thermophysical parameters of SiC foam/n-docosane
物性 密度
/(kg·m-3)比热
/kJ·(kg·K)-1热导率
/W·(m·K)-1相变温度
/K潜热
/(kJ·kg-1)SiC 3200 0.75 200 —— —— PCM 790 0.65 0.3 316 252 -
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