The influence of aerodynamic/geometric parameters on the performance of the tbcc ejector nozzle

TBCC ejector nozzle is the key component of the propulsion system of hypersonic vehicle to increase the thrust characteristic of the whole envelope. Aiming at the exhaust system of TBCC engine with the first stage of Ma 0 ~ 3, the complex internal and external flow interference characteristics of TBCC ejector nozzle are analyzed and the influence of key aerodynamic and geometric parameters are studied. 1) The secondary throat produces a strong oblique shock wave in the primary flow, that reflects with the oblique shock wave at the exit of the nozzle and forms the complex flow field characteristics of the ejector nozzle. 2) The introduction of the secondary flow will not change the flow field structure of the nozzle, but can significantly reduce the intensity of shock system in the sleeve and improve the thrust performance of the nozzle; the aerodynamic throat of the primary flow appears separation because of the high pressure secondary flow, which resulting in the flow mismatching and choking of the primary nozzle. 3) Under the severe over expansion state, the thrust performance is higher when the expansion angle is reduced; The increase of the secondary throat diameter ratio can improve the over expansion state of the primary flow and increase the thrust performance; the increase of the spacing ratio causes the increase of the secondary mass rate and the decrease of the primary mass rate, but the thrust performance is less affected.