气液两相微空心阴极空气等离子体射流的研究

Nowadays, the environmental pollution becomes more and more serious in our country, bacteria such as avian influenza have broken out now and then, and the problem of drug resistance caused by the abuse of antibiotics is also very serious. Hydroxyl radicals can decompose the organic compounds and kill bacteria no-selectively, so low temperature plasma jet containing high concentration of hydroxyl radicals is one of the effective ways to solve the above problems. In order to improve the concentration of hydroxyl radicals and reduce the work cost, in this project we study the air-H2O plasma jet based on micro-hollow cathode discharge technology to increase the concentration of OH by the ionization of H2O. In this project, firstly, we study on the influence of water distribution uniformity on the electric field distortion and discharge, master their laws to find the way of uniformity of gas-liquid mixture and reduce the electric field distortion and the influence of discharge, improve the stability of discharge. Secondly, we study the influence of the parameters of water such as proportion, conductivity and PH value upon the mechanism of propagation, parameters and OH production of plasma jet. Combining with the method of pre-ionization, we can make the droplets in the working gas charged before they enter the MHCD Jet for reducing the adverse impact of water on the development of jet, then, master the rules of OH concentration, and build the foundation of the application of air-H2O plasma jet. At present, the study of Air-H2O plasma jet is still rare, the implementation of this project, therefore, is advantageous to form original achievements on Air-H2O plasma jet, and promote the practical steps in plasma jet.

现阶段，我国环境污染问题越来越严重，禽流感等细菌时有爆发，滥用抗生素造成的耐药性问题日益严峻，OH可以无选择性的彻底分解有机物、杀灭细菌，因此富含OH的低温等离子体射流成为有效解决上述问题的重要途径之一。为了提高射流中OH含量，同时降低工作成本，本项目提出对气液两相微空心阴极等离子体射流进行研究，通过电离工作气体中的水以增加OH含量。研究水分布均匀性对电场畸变、放电的影响，掌握其规律，探寻气液均匀混合的方法，降低水对电场畸变和放电的影响，从而提高放电稳定性；研究水的含量、电导率、PH值等参数对射流传播机理、射流参数、OH产量等的影响，结合预电离技术，使工作气体中的液滴在进入主放电区前荷电，以降低水对射流发展的不利影响，掌握OH浓度产生规律，为其应用奠定基础。现阶段含水空气射流还十分鲜见，本项目的实施有利于形成含水空气等离子体射流的独创性成果，有助于推动等离子体射流走向实际应用的步伐。

含水空气等离子体射流是一个重要的研究方向，因此本研究中对含水等离子体射流的模式转变，传播机理，等离子体参数和化学产物含量变化规律，以及含水等离子射流相关应用问题进行了深入研究。首先，我们发现了微空心阴极放电随电压变化的两种放电模式：随电压升高，由自脉冲模式转变为直流模式并得到不同放电模式下放电特性和产物规律；自主搭建了触发电路，利用ICCD对含水空气等离子射流的传播机理进行了研究，得出等离子的传播速度取决于空气的流动速度，提高含水量会降低等离子体传播的速度；对比脉动直流激励跟直流激励，得出脉动直流可以有效的降低射流的温度且可以增加活性氧；搭建混水系统以及湿度控制系统研究工作气体和环境水对•OH产量影响，得到工作气体和环境含水量对•OH影响的变化规律；提出预电离方式，设计出了合理的预电离放电结构，可以有效降低水对等离子体射流中电子的吸附作用；对等离子射流在灭菌，材料改性等方面进行研究，得出在含水放电等离子体在灭菌和材料改性中具有积极的影响作用，这证明了实际应用的价值。