纤维增强气凝胶复合材料等效热导率多尺度预报方法

Fiber-reinforced aerogel composites have exhibited significant potential for application in the field of thermal insulation materials due to their extremely low thermal conductivity. In this paper, a hierarchical multiscale method was proposed to predict the effective thermal conductivity of fiber-reinforced aerogel composites. First, at the microscale, a cubic hollow sphere representative volume element (RVE) model containing the aerogel pore and skeleton was constructed based on the porosity and specific surface area. The effective thermal conductivity of the aerogel material was obtained using the finite element method. Then, the mesoscale RVE model of fiber-reinforced aerogel composite was established by considering the random distribution characteristics of the fiber in-plane direction. The effective thermal conductivity parameter of aerogel was transferred into the mesoscopic RVE model to simulate the heat flux field distribution and to predict the effective thermal conductivity of fiber-reinforced aerogel composites. The deviation of the predicted effective thermal conductivity from the experimental results is less than 10%. The composite heat transfer shows obvious anisotropy. On this basis, the effects of different fiber distribution ways and fiber volume fractions on the effective thermal conductivity of fiber-reinforced aerogel composites are analyzed.