沿面型介质阻挡放电喷枪的发光特性及气体温度研究

摘要

A surface discharge plasma jet controlled by a dielectric barrier layer is developed to generate a uniform plasma plume in ambient air at atmospheric pressure through using argon as the working gas.The discharge characteristics of the plasma jet are investigated by electrical and optical methods.It is found that the discharge pulses only exist in the positive half cycle of the applied voltage and the pulse number increases with the increasing of the gas flow rate.Spatially resolved measurements are implemented on the plasma plume for the positive half cycle of the applied voltage.It has been found that the plasma plume behaves just like a plasma bullet under different experimental conditions.Each pulse corresponds to a bullet propagating process.The total light emission signal is compared with the discharge current signal,and it is found that the total light emission signal has a time lag with the discharge current signal.The delay time between them obeys the Normal distribution.It decreases with the increasing of the peak value of the applied voltage or the gas flow rate.The gas temperature of the discharge is investigated by using an optical fiber thermometer,and results show that the gas temperature increases with the increasing of the applied voltage or the decreasing of the gas flow rate.Through analyzing the gas discharge mechanism,these experimental phenomena are investigated qualitatively.%利用氩气作为工作气体,采用正弦电压驱动沿面型等离子体喷枪,在大气压空气环境中产生了均匀的等离子体羽.电学和光学测量结果表明,等离子体羽放电只存在于外加峰值电压的正半周期,并且正半周期的放电脉冲个数随气体流量的增加而增加.通过对正半周期不同位置的发光脉冲信号进行比较,发现等离子体羽均按子弹形式传播,其中每一个发光脉冲均对应一次等离子体子弹传播过程.通过对比放电电流和等离子体羽的发光信号,发现等离子体羽的发光脉冲滞后于放电电流脉冲,且该延迟时间基本服从正态分布.该延迟时间随着外加电压峰值及气体流量的增大而减小.利用光纤测温仪测量了等离子体羽的气体温度,发现气体温度随外加峰值电压的增大而升高,随工作气体流量的增大而降低.通过分析放电过程,对上述现象进行了定性解释.