Li Xue-chen, Bao Wen-ting, Jia Peng-ying, Di Cong, Yuan Ning
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Jun;34(6):1469-72.
A uniform plasma plume was generated in a coaxial dielectric barrier discharge jet through blowing argon into the ambient air at atmospheric pressure. The plasma plume was uniform along the direction of the gas flow. The length of the plasma plume was investigated as a function of the peak voltage, the driving frequency and the gas flow rate. It was found that with increasing the gas flow rate, the plume length increases when the flow rate is lower than 4 L x min(-1), and decreases when it is higher than 4 L x mic(-1). Under constant gas flow rate, the length of the plasma plume increases with the increase in the peak value of the applied voltage and the driving frequency. According to the discharge theory and based on the analysis of the turbulence and the advection, a qualitative explanation was given for the variance of plume length as functions of the experimental parameters. Results also show that there is a discharge pulse for the plasma plume in every positive half cycle, while there is no pulse in negative half cycle. The coaxial dielectric barrier discharge shows two pulses in every positive half cycle and a pulse in every negative half cycle. Analyzing these experimental phenomena mentioned above, a formation mechanism of the plasma plume was proposed. The optical emission spectra were obtained for both the coaxial dielectric barrier discharge and the plasma plume. There was no apparent difference except that some emission lines from reactive species such as OH and N2 were found in the plasma plume. Using the first negative band of, the rational temperature of the plasma plume was measured. Results show that the rational temperature of the plasma plume decreases away from the jet nozzle, and increases with increasing the peak value of the applied voltage.
在大气压下，通过将氩气吹入周围空气中，在同轴介质阻挡放电射流中产生了均匀的等离子体羽流。等离子体羽流沿气流方向是均匀的。研究了等离子体羽流的长度与峰值电压、驱动频率和气体流速的关系。结果发现，随着气体流速的增加，当流速低于4 L·min⁻¹时，羽流长度增加；当流速高于4 L·min⁻¹时，羽流长度减小。在恒定气体流速下，等离子体羽流的长度随着施加电压峰值和驱动频率的增加而增加。根据放电理论，并基于对湍流和平流的分析，对羽流长度随实验参数变化的情况给出了定性解释。结果还表明，等离子体羽流在每个正半周期都有一个放电脉冲，而在负半周期没有脉冲。同轴介质阻挡放电在每个正半周期显示两个脉冲，在每个负半周期显示一个脉冲。分析上述实验现象，提出了等离子体羽流的形成机制。获得了同轴介质阻挡放电和等离子体羽流的发射光谱。除了在等离子体羽流中发现一些来自诸如OH和N₂等活性物种的发射线外，没有明显差异。利用N₂的第一负带，测量了等离子体羽流的合理温度。结果表明，等离子体羽流的合理温度从喷嘴处向外降低，并随着施加电压峰值的增加而升高。
