固体冲压发动机环境下C/C-SiC喷管的烧蚀行为及重复性使用分析

Ablation behavior and repetitive-use analysis of the C/C-SiC composites nozzle for solid propellant ramjet

为探索C/C-SiC喷管在固体冲压发动机工作环境下烧蚀行为及重复使用的可行性,对固冲发动机C/CSiC复合材料喷管内层进行研究。研究结果表明:C/C-SiC复合材料喷管能够适应固体冲压发动机富氧、长时间的工作环境;C/C-SiC复合材料喷管收敛段的厚度有所下降,以热化学烧蚀和热机械侵蚀为主;喉部的厚度未发生明显变化,以热化学烧蚀为主;扩张段的厚度未发生变化,只有轻微的氧化。喷管内层的环向弯曲强度和轴向弯曲强度较试验前均有所降低,收敛段下降较多,而扩张段下降较少,但仍能满足重复使用要求;应对试验后喷管内层再进行分区化学气相沉积SiC涂层,提高喉部上游的抗氧化性能,提高其重复使用时的工作可靠性。

In order to explore the ablation behavior and repetitive-use feasibility of the C/C-SiC nozzle in the solid propellant ramjet,the C/C-SiC composite nozzle was experimentally investigated.The results show that the C/CSiC composite nozzle can work safely under the oxygen-rich combustion environment of the ramjet for long test duration.The thickness of convergent section of the nozzle reduces and the ablation mechanism are suggested as the thermochemical ablation and thermal-mechanical erosion.Thermochemical ablation is the dominated ablation mechanism for the nozzle throat with the thickness not reduced appreciably.No obvious oxidation and thickness reduction are observed in the divergent section of the nozzle.The circumferential and axial flexural strength of the convergent section descend obviously while the divergent section descend insignificantly after test,which can also satisfy for repetitive-use of the nozzle.Hence for the safety and reliability of the repetitive-use nozzle,chemical vapor deposition SiC coating in different positions of the after-test nozzle should be optimally designed for improving the anti-oxidation performance of the throat upstream.