Numerical Study on Flow Characteristics of RBCC Inlet during Ejector-to-Ramjet Mode Transition

RBCC engines can operate efficiently in a wide fight range, which is promising for the propulsion system of the space transportation and supersonic cruise aircraft. During the mode transition of RBCC engines, the parameters vary considerably. Particularly, in the ejector-to-ramjet mode transition, the matching requirements between the inlet and the combustor of the RBCC engine are improved. And the integration of the embedded rocket introduces many new characteristics to the flow field of RBCC inlet. The flow characteristics of the inlet during the ejector-to-ramjet mode transition are numerically studied, and the result shows that the impact of the rocket jet makes the super/supersonic shear layer coexists with the sub/supersonic shear layer. Regarding the operation stability after the mode transition, reducing the rocket pressure to 1/5 is a better scheme comparing to the control methods of directly shutting down the rocket and reducing rocket pressure to 1/2, which can provide stable subsonic flow field and reinforce the pressure resistance. And during the dynamic mode transition, the control scheme of reducing rocket pressure to 1/5 demonstrates more stable combustor pressure.