Ablation characteristic of the pierced C/C composite nozzle in a combustion gas generator

Ablation property of the pierced C/C composite nozzle was investigated via fire testing by a combustion gas generator which simulated oxy-rich combustion environments of the liquid rocket engine. Ablation mechanisms of the pierced C/C composite nozzle and effects of the combustion gas parameters were discussed. The results show that the linear ablation rate at the throat of the composite nozzle is 0.055±0.029mm/s, and the mass ablation rate is 0.186kg/(m²·s). Ablation behavior of the pierced C/C composite nozzle is directly affected by the compositions, temperature, pressure and the velocity of combustion gases, which shows a non-uniform process. Ablation in the regions ranging from the downstream of the convergent section to the throat is the most severe. Ablation mechanisms of the pierced C/C composite nozzle are cooperation of thermo-chemical ablation and thermo-mechanical erosion. The former is primarily dependent on the combustion temperature and concentrations of H₂O and CO₂, while the latter is influenced by the pressure and velocity of the combustion gas.