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An experimental and computational investigation of supersonic film cooling was conducted on a subscale model of a rocket engine nozzle. A computational model of a convergent-divergent nozzle was generated, incorporating a secondary injection module for film cooling in the divergent section. Computational fluid dynamics simulations were run on the model and different injection configurations were analyzed. The computational fluid dynamics simulations also analyzed the parameters that influence film cooling effectiveness. Subsequent to the computational fluid dynamics analysis and literature survey an angled injection configuration was found to be more effective, therefore the hardware was fabricated for the same. The fabricated nozzle was later fixed to an Air-Kerosene combustor and numerous sets of ex-periments were conducted in order to ascertain the effect on film cooling on the nozzle wall. The film coolant employed was gaseous nitrogen. The results showed substantial cooling along the walls and a considerable reduction in heat transfer from the combustion gas to the wall of the nozzle. Finally the computational model was validated using the experimental results. There was fairly good agreement between the predicted nozzle wall temperature and the value obtained through experiments. [ABSTRACT FROM AUTHOR]

Carbon/carbon composites have been typically used to protect a rocket nozzle from high temperature oxidizing gas. Based on the Fourier's law of heat conduction and the oxidizing ablation mechanism, the ablation model with non-linear thermal conductivity for a rocket nozzle is established in order to simulate the one-dimensional thermochemical ablation rate on the surface and the temperature distributions by using a written computer code. As the presented results indicate, the thermochemical ablation rate of a solid rocket nozzle calculated by using actual thermal conductivity, which is a function of temperature, is higher than that by a constant thermal conductivity, so the effect of thermal conductivity on the ablation rate of a solid rocket nozzle made of carbon/carbon composites cannot be neglected. [ABSTRACT FROM AUTHOR]