Arc Jet Testing and Modeling Study for Ablation of SiFRP Composites in Shear Environment

The ablation process of a silica fiber-reinforced polymer (SiFRP) composite under aerodynamic heating and a shear environment was investigated by experiments and numerical study. The flat plate samples were tested in an arc jet wind tunnel under heat flux and pressure ranging from 107 W/cm² at 2.3 kPa to 1100 W/cm² at 84 kPa. The heating surface experiences shear as high as 1900 Pa. The in-depth thermal response and ablating surface temperature of the specimens are measured during ablation. According to the ablation experimental results, a multi-layer ablation model was established that accounts for the effects of carbon deposition, investigating the thermophysical properties of the ablation deposition layer. The accuracy of the proposed ablation model was evaluated by comparing the calculated and experimental surface ablation recession and internal temperature of a silica-phenolic composite under steady-state ablation. Carbon-silica reaction heat is the important endothermic mechanism for silica-reinforced composites. The research provides valuable reference for understanding the ablative thermal protection mechanism of silicon-phenolic composites in a high shear environment.