Numerical simulation for operation process of ejector/ramjet mode transition of RBCC

Four different mode transition scheme integration numerical investigation for combustion flow field of inlet and combustor was carried out. The transformation rule of flow and combustion mode and inlet operation state during the mode transition transient process was investigated. The results show that the main cause of thrust fluctuation is the discontinuity of combustion and heat reaction area along the flow direction and the reserved hot gas of primary rocket plays the role of flame holder and combustion enhancement. Reasonable mass flow rate of the reserved hot gas can not only shorten the mode transition time, but also can improve the specific impulse of RBCC. Based on numerical simulation result the mode smooth transition scheme through modulating the fuel injection scheme and throttling style of primary rocket was brought forward. The mode smooth transition scheme is validated by numerical simulation. The numerical results may provide combustion control method to be used in experiment.