AC激励下的针-水电极等离子体特性

Characteristics of AC Excited Plasmas with Needle-water Electrodes

为研究AC激励产生的等离子体的物理特性,通过电压电流波形测量和高速摄影仪拍摄对AC激励产生针-水电极等离子体的电特性和放电现象进行了研究,并通过比色分析法对生理盐水中生成的H2O2浓度进行了测量。研究表明:20kHz激励下的针-水电极的放电过程存在脉冲模式和连续模式2种工作模式。在脉冲工作模式下,当电极两端电压极性发生改变时,等离子体熄灭,每1个电压周期都需要较大的电压来击穿气体间隙,但此击穿电压比初始击穿电压低许多倍。在连续工作模式下,等离子体放电强度变强,且持续存在于放电间隙。针-水电极放电产生的等离子体可以在生理盐水中有效地生成H2O2,且在脉冲工作模式下生成H2O2的效率更高。然而,由于Fenton反应的影响,AC激励针-水电极放电等离子体对生理盐水的处理时间应≤50s。

In order to study the physical property of AC excited plasmas, the electrical characteristics and discharge phenomena of AC excited plasmas with needle-water electrodes were investigated by voltage-current waveform measurement and high-speed photography. Meanwhile, the concentration of consequently formed H202 in saline solution was measured by colorimetric method. It is shown that, there were two working modes existing in the 20 kHz plasmas with needle-water electrodes： the pulsed mode and the continuous mode. The plasma was quenched when the voltage polarity changed in the pulsed mode, thus a higher voltage, which yet was less than the initial breakdown voltage, was required to break down the gas gap in each cycle of the applied voltage. In the continuous mode, the plasma had higher discharge intensity and always existed in the discharging gap. H202 could be effectively produced in saline solution with the plasmas produced by the discharge of AC excited needle-water electrodes, and the pulsed mode discharge had higher efficiency of H202 production. However, the plasma treatment time could not exceed 50 s due to the Fenton reaction.