Investigation of Carbon–Carbon Nozzle Throat Erosion in a Solid Rocket Motor Under Acceleration Conditions

Abstract

Based on the serious issue of the significant ablation (erosion) difference of nozzle throat in a solid rocket motor (SRM) during its operation on the ground and in the atmosphere, a numerical and experimental investigation of carbon–carbon (C/C) nozzle throat erosion in solid rocket motor under specific acceleration (overload) conditions was conducted. This paper work’s results show that the erosion rate of nozzle throat in the acceleration direction is significantly higher than it is in the non-overload direction, which is defined as throat deviant ablation. In the case studied in this paper, the nozzle throat’s deviant ablation rate in the overload direction is 5 times greater than it is in the non-overload direction when the lateral overload reaches 30 g. Moreover, a sharp, and nearly linear, rise in the nozzle throat’s deviant ablation is observed as the lateral overload increases. Since the lateral acceleration will change the particles’ trajectory, the particles will move towards the lateral direction. This will in turn aggravate the chemical ablation and mechanical erosion processes, leading to throat deviant ablation. This means that the increase in the throat erosion rate in the overload region is so abominable that it must be taken into account in the design of a nozzle and the prediction of SRM performance under acceleration conditions.