Surface and volumetric ablation behaviors of SiFRP composites at high heating rates for thermal protection applications

An irreversible ablation process of a silica fiber reinforced polymer (SiFRP) composite under various thermal conditions was investigated using a numerical and experimental study. Both an oxyacetylene torch and a solar radiant heating facility were developed and used to simulate the rapid heating process. A theoretical model was proposed to predict the surface ablation behavior of SiFRP composites when only steady-state ablation is considered. The accuracy of the model was evaluated by comparing calculated and experimental surface ablation recession rate and wall temperature for a silica/phenolic composite. The effect of variable thermal and transport properties on ablation behavior was analyzed. Furthermore, a model for predicting the volumetric ablation behavior was presented. The heat transfer, generation of decomposition gases and their subsequent diffusion process in the internal material were simulated. This study would provide a fundamental understanding for the design of high temperature thermal protection system.