Research On Nonlinear Adaptive Model Of Variable Cycle Engine

With the development of engineering science,the variable cycle engine has become the development focus of the current aero-engine field due to its high unit thrust supersonic cruise and low fuel consumption subsonic cruise.In order to study the performance characteristics and control laws of variable cycle engines,it is necessary to establish an accurate variable cycle engine component-level model.The general manual model correction method requires a lot of labor cost and time cost.Therefore,the thesis studies the nonlinear adaptive model of the variable cycle engine.The variable cycle engine component level model is established,and the rationality of the nonlinear model is verified by steady state simulation and dynamic simulation.The thermodynamic calculation method of each component flow path is improved,and the real-time performance of the component level model is improved.It lays a foundation for the subsequent research on variable cycle engine control law and adaptive modeling.The control law of the above-idle state and the afterburner state of the variable cycle engine is studied.Aiming at the problem of excessive thrust jitter during mode switching,the correlation between the measurable parameters of the engine bench test and the thrust is analyzed.The neural network thrust estimator is established as a reference,and the direct thrust control of the variable cycle engine is studied.The adaptive update strategy of the components of the variable cycle engine is studied,and the common problems in the process of model correction are analyzed and solutions are proposed.The relationship between the component characteristic correction coefficient and the characteristic line scaling factor is calculated,and the adaptive update of the variable vane component characteristics is realized.The thesis verifies the validity and engineering applicability of the nonlinear adaptive model of the variable cycle engine.