一种新型大气压毛细管介质阻挡放电冷等离子体射流技术  

A novel cold plasma jet generated by capillary atmospheric dielectric barrier discharge

作　　者：孙姣[1] 张家良[1] 王德真[1] 马腾才[1] 

机构地区：[1]大连理工大学三束材料改性国家重点实验室,大连116023

出　　处：《物理学报》2006年第1期344-350,共7页Acta Physica Sinica

基　　金：大连理工大学青年教师培养基金

摘　　要：介绍一种结构设计简单、操作运行方便的新型毫米量级大气压冷等离子体射流发生技术.这种射流可以在大气压条件下,利用多种工作气体(如Ar,He,N2),通过毛细管介质阻挡放电(DBD)的方式实现.使用频率为33kHz,峰值电压为1—12kV的双向脉冲电源,利用Ar,He,N2等工作气体,在毛细管内形成了稳定的冷等离子体射流.放电区域的光辐射空间分布利用商用CCD摄像机记录,从中研究放电形态和空间分布,观察到了在DBD区域的流动气体放电和在毛细管出口处形成的等离子体射流.在DBD区域,气体静止时发生的是丝状放电,随气流速度的增加逐步转为类辉光放电.在毛细管出口处的等离子体射流区,等离子体的发光强度随气体种类和流速的不同而明显改变.实验中,利用焓探针测量气体的流速,得到了在不同气体中形成的等离子体射流的临界流速是3—8m/s.射流的射程随气体流速的增加而增加,不同气体产生的射流射程差别很大,当He流速为20m/s时,其射流最长达到44mm左右.但当He流速超过20m/s时,He等离子体射流就变得不稳定,出现涡流,而且射程变短.He射流的发射光谱结果显示,其激发温度在2000—3000K之间,远低于大气压电弧射流的激发温度.由此显示,这是一种冷等离子体射流.An easy-operated and effective scheme is presented to generate a novel kind of atmospheric cold plasma millimeter jet. The jet operates with many kinds of working gas at atmosphere pressure, such as Ar, He and N2, in a capillary quartz dielectric barrier discharge （DBD） system powered by a pulsed power source with a frequency of 33kHz and variable voltage of 1-12kV. Via an CCD imager, the initial discharge filaments in the DBD gap are found to be transformed into diffusion discharge or glowlike discharge by the flowing gas through the DBD gap, and a plasma jet formed in the outlet of the capillary is viewed simultaneously. The critical velocity of the gas flow for the plasma jet formation is determined to be 3-8m/s for different working gases by a well-designed enthalpy probe. The jet range for a special gas can be changed by the increase of the gas flow velocity while the jet range for different gases varies a lot and the helium jet takes the longest range of about 44mm when the helium flows at a velocity of about 20m/s. Beyond the velocity limit of 20m/s for laminar helium flow, the jet of helium plasma becomes torrent and unstable and its range turns shorter. Based on the OES analysis of He plasma jets, it is determined that the excitation temperature of He jets lay in the range 2000K-3000K, which is much lower than the excitation temperature of a normal arc plasma torch and hints that the jet is cold especially when compared to the arc plasma torch.

关 键 词：冷等离子体射流 毛细管介质阻挡放电 射流射程 射流激发温度 

分 类 号：O531[理学—等离子体物理]