High Bypass Ratio Turbofan Engines Transition Control Optimization And Flight/Propulsion Modeling

The optimization of large turbine engine transient control plays an important role in improvingthe safety of flight and minimizing the accident rate. The purpose of engine transient control optimizeis to reduce the response time while maintaining the engine temperature and enough surge margin,and avoiding overspeed. Transient optimal control can also enable the plane to operate in safesituation, and recover thrust rapidly under some emergency situation.In order to figure out the impact of optimized engine acceleration on airplane performance, theB747-100model of taking off/six degrees of freedom in air has been built according to theaerodynamic data of a civil aircraft, the component level model of a turbofan engine with high bypassratio was also built based on thermodynamics. A flight/propulsion model has been established afterconsidering the coupling relationship between the two models.SQP algorithm was adopted to optimize the transient control of turbofan engine and theoptimization can reduce the response time of engine acceleration process. The test on theflight/propulsion model simulated the phase of emergency power up in the situation of one enginefailure or wave-off.In order to rescue an aircraft out of danger when its traditional control surfaces was lost controlin case of hydraulic system failure, a control method was designed that can control aircraft attitudeswith only thrust change. Verification of the thrust change influence on aircraft attitude was carriedout, that is to say, the yaw and roll of the aircraft was controlled by the thrust difference of the leftand right engine, and the pitch was controlled by synchronous thrust change of two engines. Andthen TOC (throttle only control) was realized and its effectiveness was validated by an emergencylanding simulation.To realize the3D visual flight simulation, the3D simulation software was developed withintegrated application of VegaPrime and VS2005. On the basis of the3D model of OpenFlight format,the civil aircraft visual simulation has was accomplished, which owned the properties of switchableinner/outer cockpit view, movable control surface, manipulate manner similar to the real aircraft anda friendly man-machine interface.