Optimized chemical reaction mechanisms for accurate simulation of hypergolic propellant combustion

In order to improve the numerical simulation accuracy of the combustion flow process of hypergolic liquid rocket engines, the paper optimizes the reported global reaction mechanism and obtains a new reaction mechanism, which is applied to a liquid-liquid coaxial swirl pre-combustor. Firstly, the 3D simulation of the pre-combustor with liquid-liquid coaxial swirl injection was analyzed by using different ratios of chemical reaction mechanisms. The simulation results indicate that the combustion temperatures of two reported reaction mechanism model were low, and the reaction ratios and the types of products had a significant influence on the simulation results. On the basis of the reported reactions, the chemical reaction mechanism was optimized by considering fuel decomposition and calculating the relevant reaction enthalpy. Then, the optimized reaction mechanism was applied to liquid-liquid coaxial swirl pre-combustor. According to the numerical results, the error of average gas temperature between the flow field of optimized reaction mechanism and the performance parameter is 7.8%, which is reduced by 24.6% and 28.92% compared to the error of the reported chemical reaction mechanism. The numerical work lays the foundation for the establishment of a high-precision simulation model of hypergolic liquid rocket engine, which is conducive to the improvement of the performance evaluation and prediction capability of hypergolic liquid rocket engine.