Volume radiation-ablation thermal response model and analysis of lightweight needled quartz fiber/phenolic aerogel composite

In planetary entry and Earth return missions, hypersonic high-enthalpy gases lead to significant thermal radiation effects on the spacecraft's surface. The radiative transfer mechanism differs from thermal conduction modes and the impact of volume radiation effects depends on the radiative properties of the thermal protection materials. The high porosity and semi-transparent characteristics of lightweight needle-punched quartz fiber/phenolic aerogel (NQF/PRA) composites facilitate the transfer of radiative heat flux. The volume radiation-ablation thermal response model for NQF/PRA composites, which established by introducing the volume radiative transfer equation (RTE) into the traditional ablation model. Comparison with experimental results shows that the volume radiation-ablation model provides higher predictive accuracy than the traditional model. High absorption coefficient mitigates internal ablation, while accelerating surface ablation of NQF/PRA composites. High scattering coefficient weakens internal ablation, but has little effect on surface ablation. High proportion of radiative heating accelerates the pyrolysis of the phenolic within the composites, thereby generating higher internal pyrolysis gas pressure. High proportion of convective heating increases the ablation recession rate on the composite surface.