Study On Dynamic Characteristics Of Scramjet Fuel Supply And Control System

Along with the rapid development of Scramjet,the practical application and engineering of Scramjet is faster and faster.So it is necessary to conduct the thorought research to the integrated design and system integration of Scramjet.Thus,in this work,a scheme of motor pump fuel supply and control system for scramjet was proposed.And investigation on system modelling,dynamic characteristics analysis and control system design,etc were carried out carefully.Firstly,this work established simulation model of the motor pump fuel supply system in AMESim software.And the feasibility of fuel supply system was verified.The study results show that the PID controller designed for speed closed-loop control of the motor pump has a perfect dynamic reponse characteristics.The flow valve simulation model was established to study the dynamic characteristics of three valves during their operating process.And the feasibility and the accuracy of tuning fuel injection distribution was verified comprehensively.And then,in order to analyze the effect of distribution of fuel injection,a variety of fuel injection scheme was designed.And the optimal fuel distribution scheme was obtained by comparing specific impulse of each scheme through data mining method.The research results indicate that the thrust under fuel injection in the front of combustion is largger when Mach number is less than 5.3,while the thrust under fuel injection in the behind of combustion is largger when Mach number is more than 5.3.At last,this work analyzed basic control requirements of scramjet.And a thrust control law and inlet starting protection control law was designed.By co-simulation of AMESim and Simulink software,the control laws designed here can meet the control requirements.The research results show that the control law of inlet starting can effectively prevent the inlet unstarting phenomenon caused by large combustor pressure.And a maximum equivalence ratio can be obtained for the scramjet to output a maximum thrust performance based on the inlet starting security boundary.Thrust control law can adjust fuel equivalence ratio and the thrust of scramjet accurately.