3D C/SiC复合材料喷管在小型固体火箭发动机中的烧蚀规律研究

Ablation Characteristic of 3D C/SiC Composite Nozzle in a Small Solid Rocket Motor

采用小型固体火箭发动机研究了3D C/SiC复合材料喷管的烧蚀性能,分析了3D C/SiC的烧蚀机理及燃气参数对烧蚀性能的影响.结果表明,喷管喉部线烧蚀率为0.128±0.088mm/s,质量烧蚀率为0.166kg/(m^2·s);受喷管内燃气组分、温度、压强和流速等环境参数的影响,3D C/SiC的烧蚀涉及不同机理的非均匀烧蚀.喉部及其上下游过渡区域烧蚀最严重,收敛段其次,扩散段烧蚀最弱.烧蚀过程是热物理化学侵蚀和机械剥蚀综合作用的结果:涉及SiC的分解流失,SiC和碳纤维的氧化烧蚀,还涉及低速Al_2O_3大粒子的机械化学侵蚀,高速Al_2O_3小粒子的机械侵蚀等.

Ablation properties of a 3D C/SiC composite nozzle were investigated by using hot-firing test in a small solid propellant rocket motor. Ablation mechanisms of the C/SiC composites and effects of the combustion gases parameters were discussed. The results show that the linear ablation rate at the throat of the composite nozzle is 0.128±0.088mm/s, and the mass ablation rate is 0.166kg/（m^2·s）. Ablation behavior for the 3D C/SiC composite shows a nonuniform process, which is directly affected by the compositions, temperature, pressure and the velocity of combustion gases. The ablation in the divergent section, convergent section and the regions near the throat grows severe by degrees. Ablation mechanisms of C/SiC composite are the cooperation of thermo-physical ablation, thermochemical ablation and thermo-mechanical erosion, which involve the decomposition of the SiC, oxidation of the SiC and carbon fiber, as well as chemical and mechanical erosion by Al2O3 slags and particles, respectively.