For space satellite applications, mass, size, and environmental stability are major concerns due to flight/launch constraints and anticipated life times. Rigid foam offers potential usage for thermal protection or insulation applications. In this study, the heat transfer property of a foam material is examined as a function of its properties, including density, porosity and strut size. Physical and mathematical models are developed to account for conduction and radiation (absorption, emission and scattering) in a monolithic foam. The spectral extinction coefficients of SiC foams (with and without aerogel filling) with different SiC foam densities and pore sizes are measured experimentally at room temperature. SiC foam and aerogel-filled SiC foam are considered to be semitransparent, because radiation can penetrate through the pore (or void) space and/or foam skeleton (solid matrix), depending on the materials from which the foams are made. The radiative transfer equation is solved using the spherical harmonics P_1-approximations. Results from parametric calculations are compared to show the role of a range of parameters characterizing heat transfer in SiC foams to guide in foam material and microstructural configuration for effectively reducing heat transfer in potential thermal protection concepts.
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