端燃装药发动机绝热材料动态烧蚀特性研究

Study on dynamic ablation characteristics of insulator for end-burning charge motor

为了更准确预估端燃装药发动机工作中绝热材料的烧蚀变化,根据真实发动机燃面退移和包覆层破坏过程控制燃烧室流场边界移动,对流场和绝热材料烧蚀进行了耦合仿真计算。获取了流场边界移动下绝热材料的动态烧蚀特性,分析了燃速对绝热材料动态烧蚀的影响。结果表明:流场边界移动下计算得到的绝热材料炭化层厚度比固定流场边界下计算的厚度高出约0.48 mm,体现了真实发动机中由包覆层破坏导致的绝热材料烧蚀加剧现象。与高燃速条件相比,低燃速下高速气流能够冲刷破坏更大范围包覆层,引发的绝热材料烧蚀加剧现象更加明显,在绝热材料设计中需要重点关注该现象。

In order to more accurately predict the ablation changes of insulator during the operation of end burning charge motor,the boundary movement of the combustion chamber flow field was controlled based on the real process of burning surface retreat and coating layer damage.Coupled simulation calculations were conducted on the flow field and insulator ablation.The dynamic ablation of insulator under the movement of flow field boundaries is obtained and the effect of burning rate on the dynamic ablation of insulator is analyzed.The results show that the calculated thickness of the char layer of the insulator under the movement of the flow field boundary is about 0.48 mm higher than that under the fixed flow field boundary,reflecting the phenomenon of intensified ablation of the insulator caused by the damage of the coating layer in real motor.Compared with high burning rate conditions,high-speed airflow at low burning rate can erode and damage a larger range of coating layer,leading to more severe ablation of insulator,so this issue needs to be carefully considered in insulator design.