Inlet Total Pressure Distortion Modeling And Stability Analysis Of High Bypass Ratio Turbofan Engine

At present, the development of high by-pass ratio turbofan engine is promoted very fast not only in military aero-transport but also in civil air bus research field. In the acquisition of aero-engine airworthiness, aero-engine aerodynamic stability is an assessment content must be completed. The evaluation of inlet total pressure distortion is a key factor in the aero-stability evaluation of modern aero-engine, and it runs through the entire development process of propulsion system. Due to that, it is vital important to carry out the experimental research on the effects of inlet flow-distortion to the aero-stability of high by-pass ratio turbofan engine, and set up the reasonable computational and analysis methods.Relevant total pressure modeling devices was designed in this paper, in order to develop for a type of military high by-pass ratio turbofan engine. With experimental and CFD method, design methods of distortion grid and modeling plate for inlet total pressure distortion of high by-pass ratio turbofan engine was developed, and distortion grid and modeling plate was successfully designed for whole-engine distortion experiments. In addition, due to the assessment demands of engine aero-stability for one certain type, the analysis model for the effects of inlet total pressure distortion to the engine aero-stability was set up; numerical analysis research was carried out; the variation of total pressure distortion in the engine was evaluated; and the critical distortion value for the engine was acquired, with which the initiation stage of aero-instability would be determined. Results show that the maximum attenuation magnitude of total pressure distortion occurs in the fan; in addition, the fan enters into unstable state first when the engine reaches its critical total pressure distortion value at high speed, while the booster initiates the engine aero-instability at low speed.