双环状电极大气压等离子体射流的时间分辨诊断
TIME-RESOLVED DIAGNOSTIC OF ATMOSPHERIC PRESSURE PLASMA JET WITH DOUBLE-RING ELECTRODE
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摘要: 大气压等离子体射流在众多领域中发挥着至关重要的作用, 其中, 拥有双环状电极结构的射流装置表现十分突出, 此类装置具有结构简单、放电稳定的优势, 并且产生的射流长度较长、温度较低. 本工作利用ICCD相机采集技术, 对高频高压交流电源驱动的双环状电极等离子体射流进行了纳秒级时间分辨诊断. 研究发现, 在一个完整的放电周期内, 存在两个明显的放电阶段, 分别位于外加电压的正、负半周期的峰值附近, 并且在正半周期的放电阶段中, 亮度、射流长度、放电发展速度均明显强于负半周期, 值得注意的是, 仅在负半周期的放电阶段中, 才能观察到等离子体离开管口自主向前传播的现象. 本工作对于了解等离子体动力学过程, 揭示等离子体的行为规律及优化等离子体设备等诸多方面有积极地推动作用.Abstract: Atmospheric pressure plasma jet (APPJ) has played a significant role in various fields. Among various devices, the APPJ with the double-ring electrode is outstanding. It has the advantages of a simple structure, stable discharge, high flexibility, longer jet length, and lower temperature. This work utilizes ICCD camera acquisition technology to perform nanosecond level time-resolved diagnostic on the APPJ with double-ring electrode, which driven by a high-frequency and high-voltage AC power supply. The results showed that there are two distinct discharge stages in one discharge cycle, which are located near the positive and negative half-cycle peaks of the applied voltage. During the positive half-cycle discharge stage, the plasma brightness, length, and discharge development speed are significantly stronger than in the negative half-cycle. It is worth noting that only in the negative half-cycle discharge stage, the phenomenon of plasma propagating forward independently from the nozzle can be observed. This work has a positive promotion effect on understanding the dynamic processes of plasma, revealing the behavioral law of plasma, optimizing plasma equipment, and many other aspects.