摘要
利用空气作为工作气体,采用直流电压激励针-环等离子体喷枪,在大气环境下产生了可触摸的低温等离子体羽.利用电学和光学测量,结果表明等离子体羽存在两种放电模式:脉冲模式和连续模式.对于脉冲模式,研究发现放电频率随气体流量或电源输出电压的增加而增加.对于连续模式,伏安特性表明其为反常辉光放电.利用光纤测温仪测量了两种放电模式下等离子体羽的气体温度,发现气体温度随着电源输出电压增加或气体流量减小而升高.相比于连续模式,脉冲模式温度更低,可用手触摸,因此在生物医学领域有更大的应用价值.利用发射光谱,通过拟合的方法计算了两种放电模式的分子振动温度,发现它与气体温度随参数的变化趋势相同.
Plasma jet can generate a remote non-equilibrium plasma out of its intra-electrode region,which has application potentials in a large variety of fields.Now,it has become a key issue in low-temperature plasma research.It is important to decrease the gas temperature of the plasma plume for industrial applications,especially for bio medical application.In this paper,with ambient air used as working gas,an atmospheric pressure plasma jet in a needle-to-ring electrode geometry is developed to generate a non-thermal plasma plume excited by a direct current voltage,which has a so low temperature that can be touched directly by human body.Through electrical and optical methods,it is found that the discharge can operate in two distinct modes：a pulsed mode or a continuous mode.For the pulsed mode,the discharge frequency increases with increasing the gas flow rate or the power output voltage.For the continuous mode,the voltage-ampere characteristics are investigated for different gas flow rates,which indicate that the discharge is in an abnormal glow regime.Moreover,the gas temperature of the plasma plume is investigated through an optical fiber thermometer.It is found that the gas temperature of the plasma plume increases with increasing the power voltage or decreasing the gas flow rate.Compared with the continuous mode,the pulse mode has a lower gas temperature,so that its plume can be touched directly by a human finger.Therefore,the plasma jet in the pulsed mode is more important for the application in biomedical field.The optical emission spectrum from the two discharge modes is detected to calculate the molecular vibrational temperature.Result indicates that the vibrational temperature as a function of the experimental parameters is similar to the variance of the gas temperature.The physical phenomena mentioned above are discussed and qualitative explanations are given.These results are important for the further investigation of discharge mode and application of direct-current voltage excited plasma jet.
作者
李雪辰
张盼盼
楚婧娣
李霁媛
贾鹏英
LI XueChen ZHANG PanPan CHU JingDi LI JiYuan JIA PengYing(College of Physics Science ＆ Technology, Hebei University, Baoding 071002, China Key Lab of Photo-Electronics Information Materials of Hebei Province, Baoding 071002, China)
出处
《中国科学：物理学、力学、天文学》
CSCD
北大核心
2017年第2期74-80,共7页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家自然科学基金(编号:11575050
10805013)
河北省自然科学基金(编号:A2016201042
A2015201092
A2015201199)
河北省教育厅科研基金(编号:LJRC011)
中西部高校综合实力提升工程资助项目
