Dual-frequency Excitation Coaxial Plasma Igniter And Experimental Research

With the continuous expansion of flight airspace,the ignition environment faced by existing aircraft is becoming more and more complex,and the extreme ignition environment is getting worse.As a new type of ignition,plasma ignition technology is widely used in strengthening ignition research.However,most of the current plasma ignition technology stays in the research stage,lacking the design of igniters for practical applications.Existing ignition technology pays too much attention to the thermal effect during ignition.The ignition energy of the ignition design continues to increase.The ignition heat is not the main factor restricting the ignition boundary.At this time,the ignition boundary can be widened by promoting the chemical effect during ignition,while the dual-frequency excitation plasma Physical skills ensure that the thermal effect during ignition can also promote the chemical effect during ignition.Therefore,in this paper,the following aspects of research work are carried out for dual-frequency excitation ignition technology for practical engineering applications:Firstly,according to the actual application requirements,a comparative analysis of the structure of the discharge device used in the field of enhanced ignition is selected.The structure of the igniter is coaxial and the action mode of the plasma is jet.The centering positioning method of the conical surface is used to ensure the coaxiality and spacing of the Yin and Yang electrodes.The processing materials and processing methods of the igniter are selected to realize the integration of the dualfrequency excitation coaxial plasma igniter.Secondly,based on the dual-frequency excitation coaxial plasma igniter,a ground test platform for the igniter was designed to understand the working stage of the igniter.The influence of the mass flow velocity and the dual-frequency excitation parameters on the generated plasma was analyzed.The experimental results were analyzed and the final parameters of the igniter were selected.Furthermore,the dual-frequency excitation coaxial plasma igniter was introduced into the scramjet engine to understand the central ignition process of the scramjet under dual-frequency excitation,and the ignition of the igniter in dualfrequency excitation mode and DC excitation mode was compared and analyzed.Similarities and differences of time,the effect of dual-frequency excitation parameter changes on the ignition boundary of scramjet engines was studied and the cause of ignition failure was analyzed.It was verified that the igniter can widen the ignition boundary in dual-frequency excitation operation mode.Finally,based on the ignition experiment results of scramjet and dual-frequency excitation affecting the ignition boundary characteristics,the relationship between the amount of ignition oxygen and the amount of ignition kerosene in scramjet is analyzed.A dual-frequency excitation adaptive ignition method for engineering applications is proposed,and the adaptive ignition strategy design is completed.