纳秒脉冲电压变化速率对氩气 DBD 均匀性的影响

Nanosecond pulse power supply can provide pulse voltage with fast voltage slew rates. When it is used to drive atmospheric pressure dielectric barrier discharge (DBD), the discharge time is short, which can effectively inhibit the formation of filiform flow channel, facilitate the formation of uniform dispersion discharge state, and improve the application effect of plasma. In this paper, by fixing the pulse voltage amplitude and adjusting the rising and falling time of nanosecond pulse to change the pulse voltage slew rates, we experimentally studied the uniformity, electrical and optical characteristics of argon DBD under corresponding conditions, and quantitatively analyzed the discharge uniformity by combining the luminescence image and image gray analysis method. The results show that the rapid voltage slew rates can increase the reduced electric field strength E/n of discharge space, generate more active particles and high-energy electrons, and promote electron avalanche fusion, thus making the discharge more uniform. The electrical parameters such as air gap voltage and air gap discharge current are calculated by separating the collected voltage and current waveforms by equivalent circuit model. It is found that the increase of pulse rising time will decrease the peak value of air gap discharge voltage and current at pulse rising edge. Prolonging the time of pulse falling edge will significantly decrease the peak value of air gap voltage and current in reverse discharge of pulse falling edge, and the change degree is more obvious when the time of pulse falling edge is shorter. Through the measurement results of emission spectra, it is found that the increase of pulse rising edge and falling edge time greatly reduces the intensity of each emission spectrum of Ar. The results of this paper reveal the influence mechanism of pulse voltage slew rates on DBD uniformity at atmospheric pressure, which provides experimental basis for further optimizing discharge uniformity and improving reaction activity.