The analysis model of self-ejector(ejector for short

including cylindrical ejector and second-throat ejector) was set up in liquid rocket engine.The two equation κ-ε model was employed to simulate the turbulence.The performances and the flow field features of cylindrical and second-throat ejector were gained in same gap.According as these flow fields

the site of the shock wave

the full flow in nozzle

the coefficients of ejecting were calculated.The numerical value was compared with hot fire test value in vacuum cabin

both are same.