Flow field and ablation mode analysis of insulator under low acceleration with long operation time conditions for solid rocket motor

Focusing on the abnormal ablation of insulator of the solid rocket motor under flight condition, the three-dimensional two phase numerical simulation of a certain larger long diameter ratio tactical missile solid rocket motor under low acceleration-long duration condition was carried on. And the two phase flow characteristic of different area in the solid rocket motor flow path was analyzed. According to the ablation profiles of insulator and the detail of flow characteristic near the failure point, the insulator ablation characteristic and disabled mode were discussed and some improvment methods were brought forward. The results show that: (1) The particle concentration distribution and two phase flow characteristic in the solid rocket motor are decided by the acceleration direction and magnitude as well as geometry feature of flow path jointly. Then the ablation mechanism and failure mode are complicated and the abnormal ablation of insulator under low acceleration short duration condition must be considered. (2) The aggradation of particles on the insulator surface results in the forced heat transfer and particle erosion promotes ablation of insulator. And the groove and concave on the insulator surface resulting from particle erosion may focalize the particles and quicken the insulator ablation farther. (3) By making the solid rocket motor spinning or thickening the insulator locally, the flight safety can be improved.