基于DBD的均匀大面积等离子体射流研究

Study of large-area atmospheric pressure plasma jet based on coplanar dielectric barrier discharge

为了在标准大气压下获得均匀的大面积等离子体射流,本文提出了一种新的共面介质阻挡放电(Dielectctric Barrier Discharge,DBD)结构.该结构由两个同轴环形介质管形成放电气隙,通过管外金属膜电极施加交流电场形成气隙内的介质阻挡放电,并以此为基础实现了均匀的环形射流,其覆盖区的直径为12 mm,厚度为2–3 mm.本文研究了所提出结构的放电特性、等离子体射流发展过程,诊断了电子温度、电子密度等参量.研究结果表明,本文所获得的大面积射流其物理特性与传统的小管径DBD射流基本一致,认为大面积射流的物理发展过程为大量"正电晕放电"相互耦合推进过程.通过实验,进一步研究了电极结构和气隙结构对大面积DBD等离子体射流特性的影响,并提出了大面积DBD等离子体射流的优化原则.

In order to obtain a uniform large-area plasma jet at the atmospheric pressure,a new structure of coplanar dielectric barrier discharge(DBD)is proposed in this paper.The structure used in large-area DBD plasma jet consists of two coaxial annular dielectric tubes,and an alternating current electric field is applied by metal film electrodes outside the tubes to form dielectric barrier discharge in the air gap.Based on this configuration,a uniform annular jet is achieved,with diameter of 12 mm and thickness of 2–3 mm.The discharge characteristics of the proposed structure and the development process of plasma jet are studied.The spectra of the discharge,the electron temperature,the electron density,and the discharge waveforms are diagnosed.The results show that the physical characteristics of the large-area jet obtained in this work are basically the same as that of the traditional small-diameter DBD jet.It is considered that the physical mechanism of the large-area jet propagation is the mutual coupling propulsion process of a large number of positive corona discharges.The influence of electrode structure and air gap structure on the characteristics of the largearea DBD plasma jet is further studied by experiments,and the optimization principle of the large-area DBD plasma jet is proposed.