Characteristic Analysis And Multi-Parameter Optimization Of Dielectric Barrier Discharge Under Nanosecond Pulse

Dielectric barrier discharge(DBD),as one of many kinds of gas discharge,has always been a hot research topic because of its stable and efficient ionization of gas and the generation of a variety of active substances.In recent years,with the increasing demand for high energy and low consumption DBD generator,the combination of nanosecond pulse technology and DBD has become a new hotspot in the field.However,DBD discharge is a process of multi-physical field coupling,and the traditional experimental observation method has some limitations in the analysis of DBD discharge characteristics under nanosecond pulse,so the discharge mechanism of DBD cannot be analyzed and studied from a more microscopic point of view.In this paper,the DBD one-dimensional fluid model of argon gas under nanosecond pulse is established by using the computer numerical simulation technology.The model can not only describe the physical process of particles in the gas perfectly,but also consider the collision reaction between these particles and the chemical reaction on the surface of dielectric barrier layer.Based on this model,this paper first discussed in a complete and stable cycle of DBD discharge characteristics of the temporal and spatial evolution law,secondly,the contrast analysis of the change of the dielectric materials nanosecond pulse parameters and the parameters of DBD discharge characteristic is done,finally,using response surface analysis to the significance of the interaction between these factors is analyzed,and optimal design of solving the maximum response variable is obtained.The main conclusions of this paper are as follows:(1)The numerical simulation of DBD one-dimensional fluid model is carried out.The simulation results show that under nanosecond pulse,the gas current of DBD generates two discharges of opposite polarity at the rising and falling edges of the pulse,respectively,and the degree of the first discharge is always greater than the degree of the second discharge.In the rising stage of gas current,reduced electric field intensity,electron density and average electron energy is constantly increasing,reduced electric field intensity and average electron energy reach the maximum in the cathode fall region,The electron density reaches the maximum near the boundary of the cathode fall region,and their peak value is closer to the low voltage electrode continuously,and the width of the cathode fall region is also decreasing continuously.In the descending stage of gas current,the reduced electric field intensity,electron density and average electron energy all begin to decrease gradually,the ionization process in the gas also begins to decrease gradually,the discharge tends to go out,and the electric field in the discharge gap gradually presents uniform distribution(2)Under the influence of different pulse voltage amplitude,pulse rise and fall along time,dielectric barrier layer thickness and relative dielectric constant,the amplitude of gas current,the peak of electron density and the peak of average electron energy at the peak of gas current all decrease with the increase of pulsed-excitation applied voltage rise time and the thickness of dielectric barrier layer,but increases with the increase of pulse voltage amplitude and relative dielectric constant,Among them,the thickness of dielectric barrier layer has a very significant effect on DBD,while the relative dielectric constant has a limited effect on DBD.(3)Based on the response surface analysis method,the Box-Behnken design method was used to establish a quadratic polynomial regression equation with the pulse voltage amplitude,pulse rise and fall along time,dielectric barrier thickness and relative dielectric constant as independent variables,and the gas current amplitude as response variable,the fitting accuracy of the regression equation is verified by different evaluation indexes.The results show that the interaction among the factors has extremely significant effects on DBD:pulse rise and fall along time and thickness of dielectric barrier layer,pulse rise and fall along time and pulse voltage amplitude,pulse voltage amplitude and thickness of dielectric barrier layer;The order of significance of single factors on DBD is the thickness of dielectric barrier layer > pulse voltage amplitude > pulse rise and fall along time > relative dielectric constant.Finally,the maximum value of gas current amplitude is 8.692 A under the conditions of pulse rise and fall along time 200 ns,pulse voltage amplitude 4000 V,barrier layer thickness 1mm and relative dielectric constant 8,which is basically consistent with the predicted value of the regression model,proving that the model is reliable.