带有空穴子模型的石墨烯气凝胶复合相变材料导热系数的分形研究

在分形理论的基础上,确定了基于石墨烯气凝胶(graphene aerogel,GA)骨架复合相变材料的分形维数,并基于改进的Sierpinski地毯建立了带有空穴的导热系数预测模型。预测结果表明,对于基于GA骨架的复合相变材料,在所制得的材料孔隙率为0.7的条件下,无论空穴尺寸如何,均可将导热系数从相变材料本身的0.250 W/(m·K)提升至10.900 W/(m·K),增长幅度达40倍以上。结果显示,复合相变材料的导热系数随着孔隙率的减小而增加,且在低孔隙率下,导热系数随空穴尺寸的减小而增加。

Fractal model for the effective thermal conductivity of GA-based composite phase change material considering cavity submodel

This fractal dimension of graphene aerogel(GA)-based composite phase-change material(CPCM) was determined based on fractal theory. The model of effective thermal conductivity with hole sub-model was built based on improved Sierpinski carpet. The calculated results show that when the porosity of the synthetic GA is 0.7, the thermal conductivity of CPCM is enhanced by 40 times from 0.0250W/(m.K) to 10.900W/(m.K) regardless of the hole size. It is concluded that the thermal conductivity increases with the decrease of the porosity. And when the porosity is low, the thermal conductivity increases with the decrease of cavity size.