Effects of humidity on the dynamics and electron recombination of a pin-to-pin discharge in He + H 2 O at atmospheric pressure
Effects of humidity on the dynamics and electron recombination of a pin-to-pin discharge in He + H 2 O at atmospheric pressure
复制标题
湿度对大气压 He H 2 O 中 pin-to-pin 放电动力学和电子复合的影响
DOI：
10.1088/1361-6595/ac6130
复制
发表时间：
2022
影响因子：
3.8
通讯作者：
Brisset A
中科院分区：
文献类型：
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作者：
Brisset A
在许多应用中，控制等离子体的化学性质是保证常压等离子体的有效性的关键。为此，需要考虑原料气的湿度对排出化学的影响。详细的研究很少，其中许多研究主要是表面相互作用，掩盖了任何体积效应。在这里，负纳秒脉冲放电在He+ h2o的针脚3mm间隙几何中产生，使得由于最小表面积的体积动力学研究成为可能。通过实验和模拟研究了湿度对放电发展、电场和电子密度的影响。发现水蒸气的存在影响了脉冲开始时的电子密度（从前一个脉冲中保留下来）和点火阶段的电离率，导致放电发展速度依赖于水浓度的复杂依赖关系。采用0D全局动力学模型GlobalKin对电子衰变进行了研究。通过比较实验和模拟结果，确定了根据水蒸气浓度导致电子衰变的主要反应，并将这些反应分组在简化的动力学模型中。研究发现，随着水的浓度从0增加到2500ppm，主要反应的复杂性增加，特别是o2 +， h2o2 +和水团簇对高浓度水变得重要。本工作也为受控环境下等离子体动力学模型的验证提供了实验数据。
Control of the plasma chemistry is essential for the effectiveness of atmospheric pressure plasmas in many applications. For this, the effects of the humidity of the feed gas on the discharge chemistry need to be considered. Detailed studies are scarce and many of them are dominated by surface interactions, obscuring any volume effects. Here, a negative nanosecond pulsed discharge is generated in a pin–pin 3 mm gap geometry in He+ H 2 O that enables the study of volume kinetics due to minimal surface area. The effect of humidity on the discharge development, electric field and electron density is investigated through experiments and modelling. It is found that the presence of water vapour affects both the electron density at the start of the pulse (remaining from the previous pulse) and the ionisation rates during the ignition phase, leading to a complex dependence of the discharge development speed depending on the water concentration. The electron decay is studied using the 0D global kinetics model GlobalKin. The dominant reactions responsible for the electron decay depending on the concentration of water vapour are determined by comparing experimental and simulated results and these reactions are grouped in simplified kinetic models. It is found that with water concentrations increasing from 0 to 2500 ppm, the complexity of the dominant reactions increases with in particular O 2+, H 2 O 3+ and water clusters becoming important for high water concentrations. This work also provides experimental data for validation of kinetic models of plasmas in controlled environments.