Impact of thermal protections insulation layer on solid rocket motor residual thrust

The aim of the paper is to reproduce thermal protection ablation in solid rocket motors focusing on how it affects rocket performance. A physical model able to predict thermal protection ablation behavior coupled with an internal ballistic simulator is outlined. The main outcome of the above-mentioned model is the estimation of the residual thrust occurring after burn-out at high altitudes. The evaluation of the residual thrust is especially important for solid rocket motors used as upper stages and after burn-out operations take place in vacuum. During these phases, residual thrust is generated by the expansion of pyrolysis gases produced by the ablation of thermal protection materials. The nozzle radiative power was identified as the main source causing thermal protection material to ablate. An investigation of a commercial motor performance is conducted and discussed. A detailed explanation of the numerical methods used is provided.