【作者】 齐云；

【导师】 谭震宇；

【作者基本信息】 山东大学 ， 电工理论与新技术， 2019， 硕士

【摘要】 大气压脉冲介质阻挡放电(Dielectric Barrier Discharge—DBD)是产生气体放电等离子体的重要方式,并在工业、生物医学等领域得到广泛应用。因此,大气压脉冲DBD的放电特性、机制及在上述领域中的应用已成为研究者关注的重要课题。数值模拟是研究大气压脉冲DBD的有效方法,基于各种模型的数值模拟,人们已对大气压脉冲DBD在放电机制、特征量时空演化及其参数效应等方面开展了系统的研究。一维流体模型广泛应用于大气压脉冲DBD的模拟,而提高模型的精确度同时兼具较高的模拟效率一直是研究者努力的目标。基于指数差分法(ExponentiallDifference Scheme—EDS)的一维流体模型被广泛应用,但它在网格数较小时仅仅具有一阶精度。本文建立基于完全通量法(Complete Flux Scheme—CFS)的大气压脉冲DBD 一维流体模型,该模型对于不同网格数的选取均具有二阶精度。分别应用基于CFS和EDS的一维流体模型,对大气压氩气脉冲DBD作了系统的模拟计算。计算了放电电流、带电粒子密度和电场的时空分布、介质板两侧的累积电荷密度、电源输入功率密度和耗散功率密度等特征量,对两个数值方法CFS和EDS的收敛性以及对计算的特征量引起的差异作了比较。本文工作获得了如下结果:1.建立了基于完全通量法的大气压脉冲DBD模拟的一维流体模型。给出了这一模型的数值离散化方法,并表明了完全通量法和常用的指数差分法的差异。2.完全通量法CFS比指数差分法EDS有显著快的收敛,对于给定的精度要求,EDS需要约两倍的CFS的网格数才能满足。在网格数较小的模拟计算中,CFS比EDS具有更高的计算精度。使用适当小的网格数,基于CFS的数值模拟,不仅能够获得较准确的计算结果,同时也具有较高的计算效率。3.本模拟存在的双脉冲放电模式中,两个数值方法CFS和EDS对模拟计算的特征量引起的明显差异,主要发生在第一个放电电流脉冲以及其他特征量与第一个放电电流脉冲对应的部分,而对于第二个放电电流脉冲及其他特征量的对应部分,仅有很小的差异,揭示了引起上述差异的机理。更多还原

【Abstract】 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.更多还原