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以揭示固体火箭发动机在飞行条件下绝热层的异常烧蚀特性为目的,针对小过载、长作用时间条件下大长径比流道的发动机开展了三维两相流场的数值模拟研究,详细分析了发动机内流道内不同区域的颗粒聚集特征,并结合发动机失效部位处绝热层的烧蚀形貌进行了失效模式分析,针对性地提出了改进措施。研究结果表明:(1)不同过载条件下发动机内颗粒聚集和分布状态受过载大小和发动机流道结构共同作用且影响规律复杂,所引起的绝热层异常烧蚀模式和机理不同,特别是小过载长作用时间条件下的异常烧蚀需要引起设计者重视。(2)颗粒聚集在绝热层表面的换热或冲蚀都将引起绝热层局部烧蚀加剧,形成的“凹坑或凹槽”烧蚀形貌会造成颗粒的二次聚集效应,进而加剧烧蚀过程。(3)通过增加发动机旋转动作和局部绝热层加厚,可以提高发动机的飞行安全性。
In order to reveal the abnormal ablation characteristics of the solid rocket motor under the flight conditions, a numerical simulation study of the three-dimensional two-phase flow field is carried out for the engine with large aspect ratio under small overload and long acting time. The characteristics of particle agglomeration in different regions of the inner flow passage of the engine were analyzed. The failure modes were analyzed based on the ablation morphology of the thermal insulation layer at the failure site of the engine, and the improvement measures were pointed out. The results show that: (1) Under different overload conditions, the particle agglomeration and distribution in the engine are affected by the overload and the influence of the flow path structure and the complex law of influence, which leads to different ablation modes and mechanisms of the insulation layer, especially the small overload Abnormal ablation under the condition of long acting time needs to be taken seriously by designers. (2) The particle agglomeration on the surface of the heat insulation layer will cause the local ablation of the heat insulation layer to intensify, resulting in secondary agglomeration of the particles resulting in the secondary agglomeration of the particles. Exacerbate the ablation process. (3) By increasing engine rotation and thickening of the local insulation layer, the flight safety of the engine can be improved.