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/(m~2.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 H_2O and CO_2,while the latter is influenced by the pressure and velocity of the combustion gas.