含氧混合气体射流放电臭氧发生特性研究

发布时间：2018-02-10 22:00

本文关键词： 含氧混合气体臭氧射流放电直流增强　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：等离子体射流放电技术具有广阔应用空间,已经受到越来越多的关注。其优势在于可以将放电等离子体产生的化学活性成分“吹出”放电区域,可以解决处理工件大小受放电电极间隙限制的工艺瓶颈,同时放电区与作用区的分离可以减弱工件特性对放电稳定性的影响。射流放电技术被广泛应用在医疗、环境等众多领域。在这些应用场合中不仅要求放电稳定,而且需要产生多种化学活性成分满足不同应用需要。含氧气体中的射流放电是产生活性氧物种的常用方案,但是放电在产生诸多氧物种的同时也会不可避免地产生臭氧,而臭氧对于有些应用场合是不利的,例如：医疗领域。本文研究等离子体射流放电的臭氧产生过程,探索含氧混合气体中臭氧产生行为的规律性。分别以Ar、He为载气,通入一定比例的O2,构成含氧混合气体。利用三电极放电电极结构,施加千赫兹的交流电压,探究含氧混合气体中产生臭氧的行为。通过测量放电电压电流数据和放电照片,分离出放电传导电流,进行电学诊断。研究了电流脉冲峰值,电流脉冲宽度、电流脉冲个数、电流脉冲峰值位置相对电压峰值的超前量随放电参量的变化规律。探讨了多个参量如气体种类、电压峰值、电源频率、放电气压、氧气含量、放电功率,电极间隙对臭氧浓度的影响和相关规律,结合机理分析,证实了射流放电中臭氧产生和分解的一些动力学行为。结果表明,射流放电中臭氧的形成是一个动态过程,其合成和分解是同时发生,放电气体中臭氧浓度是两种动力学过程平衡的结果,放电参量对于臭氧形成都具有双向作用,因此存在峰值条件。为了提高射流放电强度,对放电结构进行了改造,实现了直流增强型射流放电。放电方案是：将直流增强电压加在中间驱动电极上,在环形悬浮电极上施加交流驱动电压,接地电极保持。研究了在此放电结构下,Ar/O2、He/O2混合气体中臭氧浓度随直流正偏压、直流负偏压及施加直流偏压位置的变化,结果表明：施加直流电压之后,射流放电体积和放电功率都有增强,达到了增强放电电子密度的目标。与此同时,臭氧的浓度可以维持几乎不升高。
[Abstract]:Plasma jet discharge technology has attracted more and more attention due to its wide application space, and its advantage is that it can "blow out" the chemical active components produced by discharge plasma. It can solve the process bottleneck which the size of the workpiece is limited by the gap of the discharge electrode, and the separation of the discharge zone and the action zone can weaken the influence of the characteristics of the workpiece on the discharge stability. The jet discharge technology has been widely used in medical treatment. Environment and many other fields. In these applications, not only discharge stability is required, but also a variety of chemical active components should be produced to meet different application needs. Jet discharge in oxygen-containing gases is a common method for producing reactive oxygen species. However, the discharge will inevitably produce ozone while producing many oxygen species, and ozone is unfavorable to some applications, for example, in the medical field. This paper studies the ozone generation process of plasma jet discharge. To explore the regularity of ozone production behavior in oxygen-containing mixed gases, the mixture of oxygen was formed by using Arhe as carrier gas and O _ 2 as carrier gas respectively. The three-electrode discharge electrode structure was used to apply the AC voltage of KHz. By measuring discharge voltage and current data and discharge photos, the discharge conduction current is separated for electrical diagnosis. The peak value of current pulse, current pulse width, number of current pulses are studied. The variation rule of the peak position of current pulse relative to the peak voltage with discharge parameters is discussed. Several parameters, such as gas type, voltage peak, power supply frequency, discharge pressure, oxygen content, discharge power, are discussed. The effect of electrode gap on ozone concentration and its correlation law, combined with mechanism analysis, confirmed some dynamic behaviors of ozone generation and decomposition in jet discharge. The results show that the formation of ozone in jet discharge is a dynamic process. The concentration of ozone in the discharge gas is the result of the equilibrium of two dynamic processes. The discharge parameters have bidirectional effect on the formation of ozone, so there is a peak value condition in order to increase the discharge intensity of the jet. The discharge structure is modified to realize the DC enhanced jet discharge. The discharge scheme is that DC enhanced voltage is added to the intermediate drive electrode and AC drive voltage is applied to the annular suspension electrode. The change of ozone concentration in the mixed gas of ar / O _ 2 and he / O _ 2 with positive DC bias, negative DC bias and the position of DC bias applied under this discharge structure is studied. The results show that when DC voltage is applied, Both the discharge volume and the discharge power of the jet have been enhanced to achieve the goal of enhancing the electron density of the discharge. At the same time, the concentration of ozone can be kept almost unchanged.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ123.2

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