预测纤维增强气凝胶复合材料热导率的研究进展∗

摘要

SiO2气凝胶复合材料具有纳米尺度结构和极低热导率，作为隔热保温材料在航天航空、建筑和其他工业领域具有重要的科学和应用价值。根据纤维在气凝胶基体中的不同分布方式，概述了预测 SiO2气凝胶复合材料的气固耦合热导率的研究进展；基于纤维和气凝胶的消光系数的不同计算方法，概述了预测 SiO2气凝胶复合材料的辐射热导率的研究进展。并提出了纤维增强气凝胶复合材料体系存在的跨尺度、多物相、分级及相互耦合等仍需进一步解决的难题，结合最新发展的格子 Boltzmann 方法(LBM)，指出了预测 SiO2气凝胶复合材料等效热导率的可能发展方向。%SiO2 aerogel composites with nano-scale structure and very low thermal conductivity have widely been used in aeronautics and astronautics,construction and other industries for thermal insulations.The research de-velopment in the conductive thermal conductivity of the SiO2 aerogel composites are reviewed according to the various distribution modes of reinforced fibers in aerogel matrix.Based on the calculation methods of the extinction coefficients of aerogels and fiber reinforcements,the advances in the radiative thermal conductivity of the SiO2 aerogel composites are demonstrated.The existing difficulties in predicting the effective thermal conductivity of the SiO2 aerogel compo-sites are generalized relevant to the cross scale,multiphase,classification and interconnection in the fiber-reinforced SiO2 aerogel composites.The perspective of the accurate prediction of the effective thermal conductivity of SiO2 aero-gel composites is also proposed involving a newly developed method - lattice Boltzmann method.