Multiphase radiation mechanism based dual-scale ablation model for woven thermal protection materials

Deep space exploration is a significant focus in the aerospace field, encompassing missions to celestial bodies such as Mars, Venus, and beyond. During exploration, the thermal protection system (TPS) of detectors must endure extreme environmental conditions, characterized by high temperatures, pressures, and diverse atmospheric compositions, as exemplified by Venus (97 % CO₂, 92 bar). Accurately predicting the TPS material response is crucial for mission success. Based on ‘multiphase radiation’ mechanism, this paper introduces a dual-scale material response model for woven composites. Following validation through oxyacetylene ablation tests, simulations are performed on two different woven structures — 2.5D shallow cross-linked and 3D orthogonal — at various flow conditions. The study reveals that the surface emission power is composed of three main components: the intrinsic emissivity of the solid phase, the morphology of the mesostructure, and the spectral radiative properties of the mixed gas on the surface. The results demonstrate that mesostructure enhancements lead to respective increases in emissivity of 9.6 % and 18.3 % for the two structures. The enthalpy value has a negligible effect on the enhancement of surface emissivity, while pressure has a significant impact on the 2.5D structure. At 10 atm pressure, there is a 9.85 % enhancement over the mesostructure, and at 50 atm, there is a 28 % increase. Pressure has a minimal impact on the 3D structure.