氩气等离子体射流诱导水生成OH自由基的研究

The Characteristic Research of·OH Induced by Water on an Argon Plasma Jet

·OH在众多领域中具有非常重要的作用,在国际上引起了广泛关注,而大气压等离子体射流由于不需要真空、装置简单易于携带,且具有高浓度活性粒子、高电子温度、低射流温度等优点,具有极强的应用前景,成为气体放电领域的重要研究课题。特别是如何诱导等离子体射流中·OH的产生已成为等离子体射流领域一个新的研究热点。国外率先报道了将水蒸汽以一定的比例混入等离子体射流工作气体中以诱导产生大量·OH的研究,然而当含水量较高时,射流会剧烈摆动,放电变得十分不均匀、不稳定。为此,本文设计了一种大气压双环电极氩气等离子体射流诱导水产生·OH的装置,通过引入超声雾化装置增加等离子体羽周围的湿度以提高·OH含量,重点研究了不同电压、流量下诱导水生成OH(A2Σ+)的生成规律;利用发射光谱法测试了装置产生·OH的含量;并利用810.41和811.48nm这两条Ar原子光谱线,计算了等离子体羽中的电子温度。结果表明等离子体羽可以诱导周围的水产生·OH,且随电压从20kV增大到28kV时,OH(A2Σ+)的产量逐渐增大;而当氩气流量从100L·h-1增大到200L·h-1时,·OH产量随着流量的增大而增大,但是当氩气流量从200L·h-1增大到600L·h-1时,·OH产量随着流量的增大而不断减小。OH(A2Σ+)的产量和电子温度变化趋势完全一致,证明了·OH的产量主要受电子温度的影响。

·OH plays a crucial role in many fields,having aroused wide public concern in the world.Atmospheric Pressure Plasma Jet,which can be achieved by portable device due to working without the vacuum environment,has the advantages of high concentration of reactive species,high electron temperature and low gas temperature.It has become an important research topic in the field of gas discharge with a strong prospect.Especially,how to induce plasma jet to produce·OH has become a new hotpot in the field of low-temperature plasma.It has been reported that mass·OH can be induced successfully when water vapor is added to the working gas,but it will be unstable when the concentrate of water reaches a certain degree.Thus,a device of argon plasma jet with a Ring-to-Ring Electrode Configuration has been designed to interact with water in the surrounding air to generate·OH under atmospheric pressure.In order to increase the production of·OH,ultrasonic atomizing device is introduced to promote water concentration around the plasma plume.The generating rule of OH（A2Σ＋）induced by water has been extensively studied under different voltages and flow rate.·OH output induced by the plasma has been tested by emission spectrometry,and at the meanwhile,Ar atomic spectral lines at 810.41 and 811.48 nm are also recorded in order to calculate the electron temperature in argon plasma plume.The results show that the water surrounding the plasma plume can be induced to produce·OH,and OH（A2Σ＋）output increases with the electrode voltage rising from 20 to 28kV.When the flow rate increases from 100 to 200L·h-1,the OH（A2Σ＋）output increases,but from 200 to 600L·h-1,it decreases.The production rules of OH（A2Σ＋）is the same as that of electron temperature.Therefore,the presumption is proved that·OH output mainly affected by electron temperature.