Impact of Thermal Protections Insulation Layer on Solid Rocket Motor Performance

The aim of the paper is to reproduce thermal protections ablation phenomenon in solid rocket motors focusing on its influence on rocket performance. A physical model able to predict thermal protections ablation behavior coupled with an internal ballistics simulator is outlined. The main outcome of the abovementioned model is the estimation of residual thrust occurring after burn-out at high altitudes whose evaluation is particularly important when solid rocket motors are used as upper stages and after burn-out operations take place in vacuum. During these phases residual thrust is generated by pyrolysis gases produced by case insulation layer due to ablation of thermal protections materials. The nozzle radiative power has been identified as the main source enabling thermal protections to ablate. An investigation of a commercial motor performance is obtained and discussed. Numerical methods are explained in detail.