Research On Ultrasonic Measurement Method Of Burning Rate Of Solid Propellant In Motor

With the rapid development of aerospace industry,the dependence on various aircraft is increasing.The combustion performance of solid propellant is an important guarantee for aircraft navigation,which directly affects the propulsion speed,working state,output power and other factors of the engine,and then affects the service life of the aircraft.Therefore,monitoring the combustion state of solid propellant has become an important part to ensure the normal operation of the engine.Under this background,this paper studies a nondestructive testing method based on ultrasonic burning rate measurement,which lays a foundation for the engineering application of solid propellant burning rate measurement.The traditional burning rate measurement of solid propellant mainly includes target line method and acoustic emission method.Both of these methods calculate the average burning rate by burning a certain length of propellant strip,which has great limitations and can not give the real-time burning rate of solid propellant.The ultrasonic measurement of burning rate studied in this paper is a kind of dynamic measurement of burning rate,which effectively makes up for the shortcomings of the existing methods.In the past,the ultrasonic dynamic measurement is only limited to the measurement of propellant strips in the laboratory,and the acoustic processing method is very simple,which is more inclined to the analysis of the factors affecting the burning rate of propellant,rather than the research on the measurement accuracy of solid propellant burning rate.In view of the above problems,this paper aims to extend the measurement method of supersonic burning rate from the laboratory measurement to the measurement of propellant burning rate in the real working state of the engine by modeling the actual propagation environment of ultrasonic in the engine.Through the analysis of the internal structure of the engine and the measurement accuracy,this paper first determines the parameters of the transmission signal,and then studies the traditional means peak measurement,draws the processing results of each frame into ultrasonic B waveform scanning,and obtains the burning rate measurement results of the traditional method by image processing method.Then,the time delay estimation of echo signal based on matched filter is studied.By analyzing the frequency domain output characteristics of matched filter,the post-processing algorithm of traditional matched filter is studied,which improves the processing gain.Through the COMSOL finite element software,the two-dimensional model of the ultrasonic propagation environment inside the engine is established.The echo signal is processed by the traditional method and the burning rate measurement method based on the matched filter.The burning rate measurement accuracy of the two methods is compared,the advantages and disadvantages of the two methods are analyzed,and the feasibility of the main research methods in this paper is verified And accuracy.