Abstract :
A multiscale thermochemical ablation model for the multidirection carbon/carbon composite throat was established in solid rocket motors. The model was established based on the reactivity of different carbon phases (fibers and matrix), the surface recession control mechanism, and spatial characteristics of the composites to understand the origin of the ablation behavior. The level set method and the weighted essentially nonoscillatory scheme were used to obtain the evolution of transient ablation morphologies on the microscale and the mesoscale. The multiscale thermochemical ablation model and numerical framework were validated by using experimental data from a small solid rocket motor and a submerged nozzle throat of large solid rocket motor. The recession rates and evolution progress of the carbon/carbon composite ablative morphology at various scales were obtained. The results were consistent with experimental data under practical operating conditions.