Modeling And Control Method Research For Scramjet

With the deepening research on scramjet,the research on hypersonic vehicles has entered the stage of engineering and practicalization.Therefore,it is necessary to carry out comprehensive modeling of scramjet system and research on the control method of the scramjet engine.In this paper,the one-dimensional analysis model of the expander cycle scramjet system is established.The influence of different injection schemes on the engine working state is studied.A hydraulically driven fuel injection controller is designed.The engine thrust and over temperature control method are raised.Research was carried out for a comprehensive engine control system.Firstly,this paper studies the working process of the expander cycle scramjet,and the mathematical model of the key parts of the engine such as the inlet,combustion chamber,tail nozzle,cooling runner and turbo pump assembly are raised.The influence of key factors such as mixing,pre-combustion shock wave train and kerosene cracking are added to the model,and finally a one-dimensional model of the expander cycle scramjet is formed.Then,the working characteristics of each component of the established expander cycle scramjet model were studied.The distribution of parameters such as pressure,temperature and Mach number in the internal flow field of engine model under different Mach number and different fuel injection positions was tested.The mechanism of different injection positions on the flow field in the engine was analyzed.The working characteristics of the turbo pump assembly was tested.The changes of the maximum combustor temperature,the the highest combustor wall temperature when the engine model outputs the same thrust under different working conditions are tested,which provides a basis for the research of engine over-temperature control method.Finally,a hydraulically driven fuel injector is designed and the injection flow control is realized by using the injector.According to the engine operating characteristics,a BP neural network based thrust control method and a fuzzy control based combustion chamber room temperature control are proposed.The engine wall temperature control method based on the cooling fuel flow control and the injection position control,combined with the established engine mathematical model,completed the control simulation of the expansion cycle scramjet engine control system.The results show that in the established engine control system,the injection controller controls the fuel flow accurately,the engine output thrust is accurate and swift,and the combustor temperature and wall temperature control intervention are timely,which can effectively ensure that the engine is working safely with the maximum performance possible.