Transient Coupled Heat Transfer in Multilayer Non-gray Semitransparent Media with Reflective Foils

In this paper, transient coupled radiative and conductive heat transfer in multilayer thermal insulation (MTI), which consists of non-gray semitransparent materials and reflective foils, is investigated for re-entry aerodynamic heating. The governing equation for combined radiation and conduction heat transfer in MTI is solved using a finite volume numerical method, whereas the radiative transfer equation (RTE) is solved using a finite difference method, in which the spectral scattering and absorption coefficients are determined using the Mie theory and the scattering phase function is modeled by the Delta-Eddington approximation. A comparison is carried out between numerical results for coupled heat transfer in non-gray MTI and those obtained by the two-flux model in which the medium is assumed to be gray. Finally, the numerical optimization of MTI is discussed.