Thermal insulation performance and heat transfer mechanism of C/SiC corrugated lattice core sandwich panel

Due to the excellent mechanical and chemical properties at ultra-high temperature, ceramic matrix composites have been promising candidates for lightweight design of future thermal protection systems (TPSs). In this work, C/SiC composite corrugated lattice core sandwich panels (LCSPs) are fabricated and their thermal insulation performances are measured by a self-developed heating system combined with infrared thermal imaging (ITI) technology. Experimental results show that the thermal insulation effect increases with core inclination angle. A new model for predicting equivalent thermal conductivity (ETC), which considers the thermal conduction, cavity radiation, thermal convection and surface radiation is established to explain why the experimentally measured ETC is lower than the predicted value of previous work. Through theoretical analysis, we find that the cavity radiation plays a dominated role in ETC prediction. To reduce or inhibit the cavity radiation, multilayer LCSPs and one-layer LCSP filled with aerogel are designed. Finite element analysis results show that two-layer LCSP is the best solution for multilayer LCSP, and the maximum ETC of one-layer LCSP filled with aerogel only is 0.226 W/(m K), much lower than that of C/SiC composite. We investigate the heat transfer mechanism and thermal insulation performance of fabricated C/SiC corrugated LCSP using experimental, theoretical and numerical simulated approaches.