Research On The Integrated Mode And The Control Method Of The Supersonic Multi State Variable Cycle Propulsion System

The next generation of combat aircraft put forward higher requirements for the engine: the characteristics of higher thrust-weight ratio,greater thrust and smaller fuel consumption to meet the flight requirements within the wide envelope.Research shows that the variable cycle engine can not only maintain good characteristics in the supersonic and subsonic flight,but also can reduce the overflow resistance,improve the engine installation performance.In this paper,an integrated research model of variable cycle engine and supersonic inlet is established,and the thrust performance and the intake distortion are studied.In view of the deficiencies in the variable cycle engine installation characteristics or outflow resistance aspects,an analysis scheme is proposed on the basis of integrating variable cycle engine and supersonic inlet system model.An integrated mathematical model,containing the inlet and the variable cycle engine is built,realizing the simulation of influences on the installation performance by varying geometry components.The impact on engine performance of variable geometric regulation was analyzed and concluded respectively.The results show when using the regulation of appropriative combination of variable geometric parts in variable cycle engine(VCE),the installed fuel consumption can be decreased by 4-6% under subsonic cruise state,accompanying with spillage drag being significantly reduced by about 12%,so the installation performance can be greatly improved.The single external bypass mode is fit for supersonic cruise or acceleration flight,which is more easy to match the flow of the inlet.The simulation results for engine speed characteristics show that: the spillage drag can be decreased by 20%,the installed thrust is enhanced by 20%,and the installed fuel consumption can be decreased by 19%,so as to obviously improve its installation characteristics.Distortion research is an indispensable part for the airplane / engine research.The program of intake air distortion is added based on the above model?The study of engine intake distortion,and the effects of intake air distortion on engine performance,especially the surge margin,are studied.The results show that the engine stability margin is greatly affected with the deepening of the distortion?The stability margin of the engine is obviously improved by adjusting the geometric component size when the distortion occurs.Finally,the engine control research is carried out to study an adaptive PI control algorithm on similar parameters and expert PID control algorithm,and the relevant control scheme is obtained by the relevant calculation.The closed-loop control scheme of the whole envelope control is studied,includes the low-pressure rotational speed and the turbo expansion ratio in the single outlet duct mode.The results show that the flight control requirements are satisfied.At last,two switching modes of variable cycle engine are studied,and the results show that the switch can be realized smoothly.