Abstract: A calculating model for simulating the internal performances of an unconventional in- let-Supersonic Through Flow Inlet being dismounted the subsonic diffuser.The model extended the definition of weight factors Q and G in the estimating equation for inlet’s boundary layer-shook interference loss proposed by Seddon and Goldsmith,So that the model can be used for inlets with a convergent internal duct such as here the Supersonic Through Flow Inlet. With curves such as losses and flow quantity supply about flying Mach number 0～2.7,the result illustrated for the first time this type of inlet’s characteristics.The model and data available will benefit a thorough study of some kinds of advance coneeived propulsion systems.

Key words: supersonic through flow, inlet, mathematical model, interference loss