Numerical Investigation of Scramjet Combustor

Thesis Abstract

Scramjet propulsion systems have the potential to be used in space, defence and civil programs. A quasi-one-dimensional model is developed which can be useful for the initial design of scramjet combustor configuration with better computational efficiency. A mixing model for wall injection of fuel has been incorporated in the model, so as to predict the combustor performance with more accuracy. A set of governing differential equations are solved in the solver by considering fast rate kinetic chemistry model for combustion. The developed model has been validated with data available in the literature for two cases (namely, Hyshot II under flight test and a generic scramjet combustor under ground test). The results indicate that the model is able to predict the wall pressure distribution with reasonable accuracy where the model assumptions hold good. Furthermore, three-dimensional simulations are carried out to optimize scramjet combustor for better performance. ANSYS CFX has been used for the flow simulation. The methodology is validated against the experimental data available in the literature. The effect of injection angle and injector diameter on thrust, combustion efficiency and total pressure loss has been observed by keeping the equivalence ratio constant. Kriging method and Non-dominated sorting genetic algorithm - II has been used for the optimization analysis. The design parameters are obtained from the optimization study, for the optimum thrust, combustion efficiency and total pressure recovery.