Enhanced Ablation Resistance of Silicone Composites in Oxygen-Rich High-Temperature Environment for Solid Fuel Ramjet Applications

The ablation resistance of silicone-based thermal protection materials in high-temperature, oxygen-rich environments remains insufficiently understood, yet it is critical for the design of thermal management systems in Solid Fuel Ramjets (SFRJs). To address this challenge, we first performed a three-dimensional two-phase flow simulation of an SFRJ combustion chamber under typical flight conditions, obtaining key parameters including temperature, pressure, and oxygen concentration. Based on these thermal boundaries, we developed an advanced ablation simulation device capable of replicating the coupled high-enthalpy oxidative and erosive environment within the chamber. Using this platform, we systematically evaluated silicone rubber composites reinforced with functional fillers and fibers. Results demonstrate that incorporating ZrB2 significantly enhances thermal stability and promotes the formation of an antioxidative ceramic layer. Furthermore, hybrid composites containing both organic and inorganic fibers exhibit superior erosion resistance due to the formation of a dense and stable char layer with a reinforced skeletal structure. This work not only provides an efficient experimental methodology for screening thermal insulation materials but also offers fundamental insights for the design of advanced ablation-resistant composites tailored to SFRJ applications.