摘要
介质阻挡放电被众多工业领域用作低温等离子体源,柱状放电是介质阻挡放电的重要形式之一,但其放电理论尚未掌握.进行大气压氦气介质阻挡放电实验,通过降低外施电压低于起始放电电压实现了柱状放电从单柱到多柱的斑图演化,拍摄了电极底面放电图像,测量了外施电压、放电电流、放电转移电荷、放电柱的柱直径和柱间距,计算了放电柱受其他所有柱施加的库仑力与磁场力.结果表明:外施电压变化瞬间电极底面放电图像呈现出动态演化过程.不同层放电柱的柱直径由中心向外层依次增大.计算发现演化稳定后放电柱所受库仑力远大于磁场力,推理存在一约束势平衡库仑力使放电柱稳定分布.不同电压、位置的放电柱所受库仑力不同:不同层的放电柱所受库仑力由最外层至中心柱依次减小,中心柱受力为0,最外层放电柱的约束势应最大而中心放电柱的约束势应该最小;外施电压降低,介质表面电荷和放电柱总数的共同作用导致库仑力增大,约束势也应有所增大,即约束势受介质表面电荷、放电柱总数与位置的共同影响.
Dielectric barrier discharge is widely used as a low-temperature plasma source in industry.Columnar discharge is an important form of dielectric barrier discharge.However,its discharge theory has not been clear yet.In this paper,the dielectric barrier discharges in helium at atmospheric pressure are carried out between parallel dielectric barrier electrodes to study the evolutionary dynamics of single-multiple columns.By reducing the applied voltages to a value lower than the initial discharge voltage,the pattern of the columnar discharge evolves from a single column into multiple columns.Discharge images from the bottom are taken to observe the evolution of discharge and measure the diameter of discharge column and spacing between columns.The applied voltage,the Lissajous figure,the discharge current,and the discharge transferred charge are measured in order to calculate the Coulomb force and the magnetic field force exerted on the column by the other columns.It is found that in columnar discharge,there is a dynamic evolution process that the single columnar discharge evolves into the two-layered columnar discharge when the applied voltage slightly decreases instantaneously.On the one hand,the column diameter is different in different layer:the column diameter increases from the center to the outer layer.On the other hand,as the applied voltage decreases,the diameter of the center column grows and the spacing between the center column and its adjacent column decreases.The calculations show that the Coulomb force is far greater than the magnetic field force when the evolution is stable,which indicates that,as mentioned in the established knowledge,there is a confinement potential to balance the Coulomb force,thereby keeping the distribution of discharge columns stable.Furthermore,the results also show that the Coulomb force on the discharge columns at different voltage and position is different.The strength of Coulomb force on column is different at different layer:it decreases from the outermost layer to the center column,which is zero on the center column.Based on the balance between the Coulomb force and the confinement potential in columnar discharge,it is suggested that the strength of the latter may also follow the same law.In addition,as the applied voltage decreases,the charges accumulated on the surface of the dielectric and the number of discharge columns both increase,which results in the increase of the maximum of the Coulomb force.The confinement potential may increase as well and follow the same law.
作者
万海容
郝艳捧
房强
苏恒炜
阳林
李立浧
Wan Hai-Rong;Hao Yan-Peng;Fang Qiang;Su Heng-Wei;Yang Lin;Li Li-Cheng(School of Electric Power,South China University of Technology,Guangzhou 510640,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第14期163-172,共10页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51777080)资助的课题.
关键词
柱状斑图放电
时空演化
库仑力
约束势
columnar pattern discharge
spatio-temporal evolution
coulomb force
confinement potential
