Research On Coupling Characteristics And Integrated Optimal Control Of Aero Propulsion System Under Supersonic State

Under supersonic state,the aero-engine installed performance,stability and safety are imposed with great challenge.Specially,the coupling problems between the supersonic inlet and engine could worsen the performance of aero engine such as installed thrust and transient performance even to surge.In order to solve the problems,this dissertation studied the the integrated aero propulsion system with modeling,testing and control methods.Specifically,they are integrated aero propulsion system modeling,performance seeking control at quasi-steady/transient state,research on aero propulsion stall detection,and high stability propulsion control.Firstly,this dissertation built the component-level model of aero propulsion system,including supersonic,engine and nozzle,which coule simulate the co-working sate of aero propulsion and installed performance in real time.Compared with traditional aero-propulsion model,the new component-level model could be used in the mechanism analysis of inlet and engine co-working and impacting factors.Meanwhile,a new trust region Newton once pass algorithm was proposed to solve the co-working equations in aircraft low Mach number.Secondly,the quasi-steady performance seeking control under supersonic cruise state was studied.The performance seeking control algorithm took the installed performances of aero-propulsion into consideration,which made the performance seeking control be possible in real application.At the same time,an improved aero propulsion degradation eastimator was proposed to eastimate the engine degraded factor.Based on the supersonic bleeding and ramp angle modulation,a new performance seeking control scheme was built with the installed parameters and control variables of inlet bleeding door angle/ramp angle,guided valve angle of fan and compressor,fuel mass flow rate,and nozzle throat area.The simulation results indicated that the new performance seeking control scheme has a better performance compared to the traditional scheme,and it is more suitable for the engineering application.Thirdly,the propulsion system transient process optimal control was sdutied.In order to implement the transient optimal controller,an inlet ramp angle controller was built based on the aero propulsion integrated model and one-dimension nonexact search method,which had a good performance in the steady and dynamic property.Based on the inlet,engine and nozzle,the transient process was optimized with the variables of inlet ramp angle,fuel mass flow rate and nozzle throat area.Fourthly,in order to research the propulsion stall law,the author proceeded the compressor stall tests with different inlet distortions and rotor speeds.With analysis in the time domain and frequency domain,a best pressure sensor location was certified to dectect engine stall with stall detection algorithm.With the correlated efficient calculated by stall detection algorithm,a compressor blade pressure model was built,which was essential and trusted to the engine stability control.At last,the aero-propulsion stability control was proposed in maneuvering operations.With transient optimized database,a new inlet dynamic controller was built.The surge margin estimated model was built and modified by the supersonic inlet fluent calculating results.With the estimated surge margin,a high stability control scheme was proposed under flight of big attack angle.In acceleration process,an active control was built by compressor blade model and stall detection algorithm.Based on the high stability control scheme and active protection scheme,a new high stability control scheme in acceleration process was proposed,which was more valuable in the engineering application.