大气压低功率表面波等离子体射流的研究

发布时间：2018-06-29 18:49

本文选题：微波放电 + 低温等离子体　；参考：《安徽理工大学》2017年硕士论文

【摘要】：与低压微波等离子体相比,大气压微波等离子体有许多独特的优点:例如,密度大、活性高及生产装置简单等。因此,大气压微波等离子体在实际生产应用和科学研究中获得广泛的关注。然而,在大气压条件下,流注放电为微波放电的常见表现形式,因此,在这样的环境下为了获得理想的微波放电需要提供很高的激发入射功率,基于此,大气压微波放电的实现代价较高,实际应用较困难。针对大气压低功率微波放电难于实现的科学技术难题,以大气压低功率表面波等离子体(SWP)射流为研究对象,采用等离子体与微波相互作用的共振耦合放电方法,借助表面波等离激元(SPP)局部加强电场便于触发气体放电的优越性,研究SPP激励SWP射流放电机制。通过构建放电实验,诊断放电过程,辅以数值模拟,分析得出SPP激励SWP射流的放电机理。本文将揭示大气压低功率微波SWP射流的电离发展过程,解释大气压微波流注气体放电的时空物理参量演变机制。本文的主要研究内容总结如下:1.首先,微波放电是一种相对较新的技术,它需要科研工作者具备一些微波工程和等离子体工程的相关知识。所以先介绍微波放电理论中的一些基本概念,然后研究探讨现有的各种类型的等离子体发生装置。因为了解这些现有等离子体源的优点和问题,有助于新型等离子体源的开发和设计。2.其次,由于微波放电的不稳定性,以及微波放电的影响因素至今还未研究透彻,对于如何在大气压条件下开发大规模、高效节能、均匀的微波等离子体仍有待研究。因此,本文设计了三种类型的同轴谐振器,并获得了 2.45GHz共振频率的微波。然后向谐振器通以流动的氩气,在只有5W的微波驱动功率下分别在周围空气中产生不同形貌的等离子体射流。3.最后,由于与直流放电和射频放电不同,微波放电的电压、电流不能直接测量。通常,需要使用复杂的系统对微波放电的正向和反射功率进行测量。因此这对于微波放电的诊断和分析是一个巨大的障碍。而本文绕开这一障碍,基于传输线理论模型,探讨了同轴谐振器的工作机制;并利用HFSS和COMSOL仿真软件建立电磁模型和流体模型,进一步探讨了同轴谐振器的放电机理。
[Abstract]:Compared with low-pressure microwave plasma, atmospheric microwave plasma has many unique advantages, such as high density, high activity and simple production device. Therefore, atmospheric pressure microwave plasma has received wide attention in practical application and scientific research. However, at atmospheric pressure, streamer discharge is a common form of microwave discharge. Therefore, in order to obtain the ideal microwave discharge, it is necessary to provide a high excitation incident power. The realization cost of atmospheric microwave discharge is high, and the practical application is difficult. Aiming at the difficult scientific and technological problems of low-power microwave discharge at atmospheric pressure, the resonant coupled discharge method of plasma-microwave interaction is adopted to study the low-power surface wave plasma (SWP) jet at atmospheric pressure. The mechanism of SPP stimulated SWP jet discharge is studied by virtue of the advantage of local enhancement of electric field to trigger gas discharge. The discharge mechanism of SPP excited SWP jet was analyzed by constructing discharge experiment, diagnosing discharge process and numerical simulation. In this paper, the ionization development of low-power microwave SWP jet at atmospheric pressure is revealed, and the evolution mechanism of space-time physical parameters of atmospheric microwave streamer gas discharge is explained. The main contents of this paper are summarized as follows: 1. First of all, microwave discharge is a relatively new technology, which requires some knowledge of microwave engineering and plasma engineering. Therefore, some basic concepts of microwave discharge theory are introduced, and then various kinds of existing plasma generation devices are studied. Understanding the advantages and problems of these existing plasma sources is helpful to the development and design of new plasma sources. Secondly, because of the instability of microwave discharge and the influence factors of microwave discharge, how to develop large scale, high efficiency, energy saving and uniform microwave plasma at atmospheric pressure is still to be studied. Therefore, three types of coaxial resonators have been designed, and 2.45GHz microwave resonance frequency has been obtained. Then the flow argon gas is connected to the resonator, and the plasma jet with different morphology is produced in the ambient air under the microwave driving power of only 5 W. Finally, the voltage and current of microwave discharge can not be measured directly because it is different from DC discharge and RF discharge. In general, complex systems are used to measure the forward and reflected power of microwave discharge. Therefore, this is a huge obstacle to the diagnosis and analysis of microwave discharge. In this paper, the working mechanism of coaxial resonator is discussed based on the transmission line theory model, and the discharge mechanism of coaxial resonator is further discussed by using HFSS and COMSOL simulation software to establish electromagnetic model and fluid model.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O53;O461

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