导热-辐射耦合传热的多尺度分析和数值模型

Predictions of the heat transfer processes in composite materials are important for designs of thermal protection structures of hypersonic vehicles. The corresponding model is also an essential part of the multiphase-multicomponent sub-model of the National Numerical Windtunnel Project. In this work, a multiscale asymptotic analysis method is used to study the problem of coupled conduction-radiation heat transfer for high temperature composite materials with periodic structures. Both the conduction equation and radiative transfer equation are analyzed. The cell problem and homogenized macroscopic conduction and radiation equations are established. The relation between effective thermal conductivity and the results of the cell problem is obtained. It is also found that the radiative absorption and scattering coefficients can be calculated from the volumetric averages in a representative element. A multiscale numerical model for conduction-radiation heat transfer in composite materials is built based on the finite volume method and the lattice Boltzmann method. The multiscale model is validated by the simulation of heat transfer in 2D materials with constant thermal properties. It is shown that the temperature fields can be effectively and accurately calculated by the multiscale model proposed. The model can be further used in the prediction of high-temperature heat transfer processes in composite materials.