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

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/C-SiC 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.