Study of the thermal adjustment of RBCC based on two-stage injections

To further improve the performance of Rocket Based Combined Cycle (RBCC) combustor in ramjet mode, one-dimensional analysis model and three-dimensional numerical simulation have been carried out to study the variation law of thermal throat and the scheme of thermal adjustment. Through the variation of above parameters in certain range, thermal throat position changes by 9% ∼ 22%. The different position of thermal throat calculated by one-dimensional model shows that the more after of thermal throat position is, the bigger of integral thrust can be obtained when the expansion ratio of combustor and total exothermic quantity are the same. Compared with the single-stage injection, adopting the two-stage strategy is more suitable for the operating characteristics of the ramjet mode. The combustion of primary fuel is mainly to achieve pre-combustion shock wave in isolator to ensure the subsonic incoming flow and the second fuel is mainly to adjust the position of thermal throat. Through grading injection can make exothermic more balanced to promote the overall pressure of combustor. The thrust performance of RBCC combustor can achieve at least 10% improvement at fly condition of Ma3-4 by using the thermal adjustment method based on two-stage injections.