An Implementation And Simulation Study Of Complete Flux Scheme In 1-D Fluid Model For The Pulsed DBD At Atmospheric Pressure

The pulsed dielectric barrier discharge(DBD)at atmospheric pressure,an important solution to generate plasmas by gas discharge,has been extensively applied for industry fields and biomedicine.Accordingly,both the discharge characteristics of the pulsed DBDs at atmospheric pressure(hereafter,called the applied DBD)as well as the corresponding mechanisms and the application of the pulsed DBDs in the above fields have become the topics being of great interest for researchers.The numerical simulation is an effective way of studying the applied DBD.Based on the different simulation models,the systematic investigations on the discharge mechanism,the spatial-temporal evolutions and parameter effects of the characteristic quantities have been proceeded for the pulsed DBD.One-dimensional(1-D)fluid model is an effective tool used widely in the simulation of the pulsed DBD so far.Especially,it is a goal for researchers to improve its precision and meanwhile to obtain a higher calculation efficiency for the used simulation model.The 1-D fluid model with an exponential difference scheme has been widely used in the study on the pulsed DBD,but this model is of only one order accuracy in the case of small computational grid number.In this thesis,a complete flux scheme(CFS)has been implemented in a 1-D fluid model to simulate the pulsed DBD in pure argon at atmospheric pressure.The present 1-D fluid model has a second-order accuracy for the different grid numbers.Based on the 1-D fluid models using the CFS and EDS,respectively,the characteristic quantities of the pulsed DBD have been systematically calculated.The considered characteristic quantities include discharge current,spatial-temporal distributions of charged particle density and electric field,cumulative charge density on both sides of the dielectric plate,mains input power density,and dissipation power density.The comparisons have been made between convergences of the two numerical schemes and the differences have been revealed between the characteristic quantities induced by the two numerical schemes.This thesis gives the following conclusions:1.A 1-D fluid model based on the complete flux scheme has been presented for the simulation of the pulsed DBD in pure argon at atmospheric pressure.The discretization method of the model has been given,and the difference between the CFS and EDS has also been shown.2.The CFS is of evidently fast convergence in comparison with the EDS.To meet a given accuracy requirement,the EDS needs a grid number twice that of the CFS.In simulation calculations of the considered characteristic quantities with a small grid number,the CFS has higher calculation accuracy than the EDS.The usage of the CFS with a properly small grid number not only gives a more accurate result but also presents a higher calculation efficiency and lower computational cost.3.There is the two-pulse discharge mode in the present simulation.With a small grid number,the numerical scheme has an evident effect on the characteristic quantities in the time region corresponding to the first discharge pulse,but only slightly affects those corresponding to the second discharge pulse.The mechanism governing the above differences has been revealed.