大气压氦氧与氩氧脉冲介质阻挡放电频率效应及活性氧生成机制研究

发布时间：2018-04-10 22:34

  本文选题：脉冲介质阻挡放电 + 放电等离子体　； 参考：《山东大学》2017年硕士论文

【摘要】：介质阻挡放电是将绝缘介质置于放电空间,常用于产生人工放电等离子体的一种气体放电方式。而大气压脉冲介质阻挡放电是一种由高压脉冲激励的新兴的介质阻挡放电方式,能够兼具介质阻挡放电和脉冲放电的优良性能,在大气压下产生高化学活性的非热平衡放电等离子体,完美地契合非热平衡放电等离子体应用领域中的实际需求,因此无论是从放电机理、特性等物理研究到等离子体生物医学、材料改性等应用研究都受到国内外专家学者的广泛关注。本论文建立并使用非热平衡放电等离子体的一维流体模型,深入地研究了脉冲频率对大气压氦氧与氩氧脉冲介质阻挡放电等离子体的机理及特性的影响,并对大气压氩氧脉冲介质阻挡放电等离子体中活性氧粒子生成机制开展了系统的研究。本文的研究工作,主要包含以下方面的内容和结果。(1)使用一维流体模型,对2%氧浓度下大气压氦氧与氩氧脉冲介质阻挡放电等离子体中放电电流密度、电场强度、平均电子温度以及活性氧粒子的时空平均粒子密度的频率效应作了比较研究;研究了 5%的高氧浓度下大气压氩氧脉冲介质阻挡放电等离子体中放电电流密度在1kHz-100kHz范围的频率效应,得到以下结论:无论是氦氧还是氩氧,一个电压脉冲周期中均发生两次极性相反的放电;频率对氦氧中的两次放电均有影响,而对氩氧中的第一次放电影响比较大,第二次放电影响很小;两种放电气体中,第一次放电峰值时刻的放电电流密度,平均电子密度和电场强度均随着频率的增加先减小后增大,存在一个特征频率,在该频率下具有最小值,且在氩氧中该特征频率比氦氧中要小;在所考虑的放电条件下,与氦氧相比,氩氧中放电更强,平均电子温度更低。在同一频率下,氩氧中的四种活性氧粒子的总生成量比氦氧中高出约一个数量级。在更高氧浓度下,氩氧第一次放电与第二次放电的放电电流密度峰值均随着频率的增加先减小后增大,存在相应的特征频率;在低于4%的氧浓度下,随着氧浓度的增加,第一次放电的特征频率呈现先增大后减小的变化,第二次放电的特征频率一直持续增加,但在氧浓度高于4%时,二特征频率基本不变。(2)对一维流体模型的边界作了优化,使用该改进的一维流体模型,对大气压氩氧脉冲介质阻挡放电等离子体中活性氧粒子生成机制开展了系统的研究,研究内容包括氧浓度为3%时四种活性氧粒子生成与消耗的主要路径及其在不同频率下相应的反应贡献,以及氧浓度为1%时长生存时间活性氧粒子的生成及调控机制,得到以下结论:氧浓度为3%时,四种活性氧粒子生成与消耗的主要路径研究中,不同频率下O(1D)与O_2(1△g)的产生均主要来源于电子与O_2的碰撞;O的产生主要来源于电子与O_2的碰撞,其次是O(1D)与O_2的反应;O_3主要是通过O与O_2的反应O_2+O_2+O→O_3+O_2产生。对于活性氧粒子的消耗,O(1D)主要是通过反应O(1D)+O_2→O+O而消耗,且受频率影响很小;O、O_2(1△g)和O_3的消耗路径发生在几个重要反应之间,其反应贡献受频率影响较大。在氧浓度为1%时长生存时间活性氧粒子的生成及调控机制研究中,在一个完整脉冲周期内,电子e、Ar+、Arr、Arm和Ar*等粒子均主要生成于脉冲作用阶段的上升沿和下降沿,并随着脉冲的关断迅速衰减为零,而O、O_2(1△g)和O_3三种活性氧粒子在脉冲关断以后仍大量存在于气隙中。O_3的空间平均粒子密度增大主要是源于反应O_2+O_2+O→O_3+O_2对O_3的产生的主导贡献;O和O_2(1△g)的空间平均粒子密度增大则主要是因为在外施脉冲电压作用下两次放电相伴的电子e与O_2发生的碰撞引起的O和O_2(1△g)的产生的骤增。
[Abstract]:Dielectric barrier discharge is the insulating medium is arranged inside the discharge space, a gas discharge mode used to produce artificial plasma. Atmospheric pressure pulsed dielectric barrier discharge is composed of a high voltage pulse excitation of the new dielectric barrier discharge, excellent performance can both dielectric barrier discharge and pulse discharge, non thermal equilibrium plasma discharge high chemical activity under atmospheric pressure, perfectly fit the actual demand application of the non thermal equilibrium in the discharge plasma, so whether it is from the discharge mechanism, physical characteristics to plasma biomedical, widely concerned by domestic and foreign experts and scholars of the application research of modified materials. This paper establish and use the non thermal equilibrium a one-dimensional fluid model of the discharge plasma, in-depth study of the pulse frequency on the atmospheric pressure helium oxygen and argon oxygen pulse dielectric barrier discharge plasma The influence mechanism and characteristics of progeny, and the atmospheric pressure argon oxygen pulse to carry out a systematic study of dielectric barrier discharge plasma reactive oxygen species generation mechanism. The research work of this thesis, the main contents and results include the following aspects. (1) using a one-dimensional fluid model of 2% oxygen under atmospheric pressure helium and oxygen argon oxygen pulse dielectric barrier discharge plasma discharge current density, electric field intensity, the average electron temperature and time of active oxygen particles average particle density frequency effect are studied; the effects of high oxygen concentration 5% under atmospheric pressure argon oxygen pulse dielectric barrier discharge plasma discharge current density frequency effect in the range of 1kHz-100kHz, get the following conclusions: both the helium oxygen or argon oxygen, a voltage pulse cycle are two opposite polarity discharge; the two discharge can influence the frequency of helium and oxygen, and The relatively large first discharge effect of argon and oxygen in the second movie sound is very small; two kinds of gas discharge, the first discharge peak discharge current density, the average electron density and the electric field strength with the increase of frequency decreases first and then increases, there is a characteristic frequency, with a minimum at the frequency and, in the characteristic frequency ratio of argon and oxygen in helium oxygen should be small; in the discharge conditions, compared with helium oxygen, argon oxygen discharge stronger, the average electron temperature is lower. At the same frequency, the total production of four kinds of reactive oxygen species in the argon oxygen about a order of magnitude higher than helium oxygen. At higher oxygen concentration, oxygen argon discharge and the first second discharge current density peak value with the increase of frequency decreases first and then increases, the corresponding characteristic frequency; the oxygen concentration is below 4%, with the increase of oxygen concentration, the first The characteristics of electrical frequency changes increased first and then decreased, the characteristic frequency second times discharge has continued to increase, but when the oxygen concentration is higher than 4%, two characteristic frequency basically unchanged. (2) of a one-dimensional fluid model boundary were optimized using a one-dimensional fluid model, the improvement of atmospheric pressure argon, oxygen pulse to carry out a systematic study of dielectric barrier discharge plasma reactive oxygen species generation mechanism, research content including the oxygen concentration is 3% the main path of four kinds of reactive oxygen species generation and consumption and its contribution to the corresponding reaction at different frequencies, and the oxygen concentration of 1% long survival time of reactive oxygen species generation and regulation mechanism, are as follows conclusion: when the oxygen concentration was 3%, the main research path of four kinds of reactive oxygen species generation and consumption in different frequency O (1D) and O_2 (1 g) is produced mainly from electronic and O_2 collision; the production of O 涓昏�佹潵婧愪簬鐢靛瓙涓嶰_2鐨勭�版挘�

本文编号：1733196