大气压空气中纳秒脉冲介质阻挡放电均匀性的研究

Uniform of Unipolar Nanosecond Pulse DBD in Atmospheric Air

为了实现大气压空气中纳秒脉冲均匀介质阻挡放电(DBD),利用上升沿15ns,半高宽30～40ns的正极性纳秒脉冲激发DBD,并由电压电流和放电图像研究DBD的特性,分析均匀放电实现的条件和特征。实验结果表明放电电流呈双极性,且电气参数要比交流及微秒脉冲DBD的高,在一定条件下可获得均匀模式放电。通过重复频率和气隙距离对放电均匀性的影响研究发现,2mm空气间隙中,双层介质阻挡时重复频率对放电均匀性影响不明显,但当间隙距离从2～8mm延长时,放电明显由均匀模式向丝状模式过渡。此外,对纳秒脉冲DBD放电均匀性与施加脉冲上升沿的关系进行了探讨。

In order to obtain homogenous dielectric barrier discharge（DBD） in atmospheric air,the uniform of nanosecond pulse DBD is studied in the paper.The DBD is excited by positive unipolar nanosecond pulse with a rise time of about 15 ns and a full width at half maximum of 30～40ns,and the conditions and characteristics of homogenous DBD are analyzed by the measurement of their electrical discharge parameters and images.The experimental results show that the discharge current exhibits bipolar and the electrical parameters in unipolar nanosecond-pulse DBD are significantly higher than that in the DBD using ac or microsecond-pulse excitation.It is found that homogenous DBD can be obtained under certain condition.Furthermore,the effects of pulse repetition frequency（PRF） and air gap spacing on the uniform of DBD show that the PRF affects less on the uniform of DBD when both electrodes are covered by dielectrics and the air gap spacing is fixed at 2mm,but the discharge significantly transits from homogenous to filamentary mode when the air gap spacing increases from 2mm to 8mm.In addition,the relation ship between the uniformity of DBD and rise time of applied pulse is discussed.