电流密度对大气压射频辉光放电等离子体特性影响的数值模拟  

Simulations for the Influences of Current Density on the Discharge Characteristics of Radio Frequency Atmospheric Pressure Glow Discharge

作　　者：王志斌[1] 聂秋月[1] 李和平[2] WANG Zhibin1, NIE Qiuyuel, LI Heping2(1. Laboratory for Space Environment and Physical Sciences, Harbin Institute of Technology, Harbin 150001, China; 2. Department of Engineering Physics, Tsinghua University, Beijing 100084, Chin)

机构地区：[1]哈尔滨工业大学空间基础科学研究中心,哈尔滨150001 [2]清华大学工程物理系,北京100084

出　　处：《高电压技术》2018年第3期896-903,共8页High Voltage Engineering

基　　金：国家自然科学基金(11405038;51577044;11475103);国家博士后基金(2015M570283);黑龙江省博士后基金(LBH-Z14081)~~

摘　　要：由裸露金属电极结构发生器产生的大气压射频辉光放电（radio frequency atmospheric pressure glow discharge,RF APGD）等离子体射流具有活性粒子浓度高、射流温度较低且可控性强等特点。为研究电流密度对大气压射频辉光放电等离子体特性的影响规律,采用数值模拟的方法,以高纯氦为工作气体,通过流体模型分别对RF APGD放电区和射流区进行了一维非稳态和二维准稳态数值模拟。论文揭示了放电电流密度对RF APGD等离子体特性的影响规律。计算结果表明：在放电区,随着放电电流密度的增加,活性粒子数密度和气体温度均显著升高,当电流密度较高时,放电由α模式转化为γ模式;而在射流区,一方面,随着放电电流密度的增加发生器出口处的气体温度和等离子体密度提高,另一方面,由于气体温度的升高会提高射流区部分去电离反应的速率,导致射流区电子和离子衰减得更快,从而使得射流区不同空间位置处的活性粒子数密度并非随电流密度增加而单调增加。Radio frequency atmospheric pressure glow discharge（RF APGD） plasmas which are produced by the plasma generators with a bare-metallic electrode configuration exhibits the features of high concentration of chemically reactive species, low plasma jet temperatures, and convenient controllability, etc. Thus, it is widely used in the fields of materials processing and modification, food engineering, environmental engineering, and biomedical science, etc. Consequently,to study the influences of discharge current density on the discharge characteristics of RF APGDs, taking high purity helium as the working gas,we employed the one-dimensional transient and two-dimensional quasi-steady fluid models to simulate the characteristics in the discharge region and plasma jet region of the RF APGDs, respectively. The influences of the discharge current density on the characteristics of the RF APGD plasmas were revealed. The modeling results show that：（1） In the discharge region, both the species number densities and the gas temperatures increase significantly with increasing in the discharge current density; and when the current density is high enough, the discharge mode transfers from the α mode to the γ mode.（2） In the plasma jet region, on one hand, both the gas temperature and plasma density at the outlet of the plasma generator increase with increasing in the discharge current density; on the other hand, the increase of the gas temperature will increase some deionization reaction rates, and subsequently, leads to a fast decay of the electrons and ions in the plasma jet region.Therefore, non-monotonic variations of the species number densities occur at different spatial locations with the increase of the discharge current density.

关 键 词：大气压等离子体 射频辉光放电 放电电流密度 放电区 射流区 

分 类 号：O461[理学—电子物理学] O53[理学—物理]