Research On Microwave Plasma Ignition

Microwave plasma ignition technology,as a new type of ignition,has many advantages: short ignition delay time,good consistency,and ignition device structure is simple,no electrodes,not only can be designed to ignite at a specific location,but also can extend the life of the ignition device,this ignition technology has been applied in the internal combustion engine,various types of gun ignition system,rocket ignition system,especially in the field of internal combustion engine research has achieved good results.In the field of gunpowder ignition,the traditional method of ignition has reached its limit in terms of improving the performance of the artillery and is difficult to meet the needs of future warfare.Based on this,the research on microwave plasma ignition in the field of gunpowder ignition is carried out in this paper,and related theoretical analysis,simulation calculations and experimental verification are carried out.In this paper,the dielectric properties of gunpowder are investigated from the analysis of its microwave ignition mechanism,and simulation studies and experimental studies are carried out on the microwave ignition device,and the experimental phenomena under different experimental schemes are finally compared and analyzed to draw the corresponding conclusions.The main elements of the study are as follows:(1)The mechanism of microwave ignition of gunpowder,including microwave heating principle,field emission principle and microwave-plasma interaction mechanism,was analyzed,which laid the theoretical foundation for subsequent numerical simulation and experimental research work.(2)The importance of the dielectric properties of gunpowder and the principle of the transmission/reflection method are discussed,and for the measurement of dielectric constants of L-and S-band gunpowder,the transmission/reflection method is used to construct a rectangular waveguide measurement system for the frequency band dielectric constants.The measurement of the air dielectric constant showed the validity of the constructed measurement system,and finally the dielectric constant and loss angle tangent of the gunpowder were obtained using MATLAB calculations.(3)In order to enhance the local field strength of the microwave ignition test device,two pairs of cone tables were added to the BJ26 waveguide,and the initial parameters were found not to meet the design requirements very well by CST simulation.Thus,the cavity was obtained at the resonant frequency point of 2.451 GHz,and the small cone tip electric field reached an order of magnitude of MV/m at the microwave input power of 1 kW.The designed cavity was then subjected to a breakdown simulation analysis using the CHIPIC software and the breakdown threshold was obtained for that cavity.Using the measured gunpowder electromagnetic parameters,the new material was defined and the medium was added to the tip of the small cone table,which was found to be effective in enhancing the electric field strength and reducing the breakdown threshold of the cavity.(4)A microwave plasma ignition experimental platform,including a microwave energy input system,a microwave transmission system and an ignition chamber,was built to observe and record the burning phenomenon of gunpowder according to the experimental scheme design,and to analyze the main ignition mechanisms of gunpowder burning under different schemes.