Influence of residual charge on repetitively nanosecond pulsed dielectric barrier discharges in atmospheric air

Abstract

The plane-to-plane dielectric barrier discharge within 5 mm air gap driven by repetitive nanosecond pulses is studied. A water resistance (WR) is connected in parallel with the discharge circuit. For the discharge without the WR, two reverse discharges occur in the falling front of the voltage pulse, and besides, the primary discharge occurs in the rising front. For the discharge with the WR, only the primary discharge takes place, and the voltage waveform is changed into the unipolar positive voltage pulse with the elevated fall time. Additionally, the discharge with the WR displays the intermediate between the traditional diffuse and filamentary modes. Moreover, the uniformity of the discharge with the WR is increased as the pulse repetition frequency decreases from 1200 Hz to 100 Hz. The above observations in the discharge with the WR are mainly attributed to the increase in the residual charge at the inception of the following pulsed discharge.

Characteristics of high-repetition-rate bipolar pulse DBD under various electrical conditions in atmospheric-pressure air

“…Furthermore, while the voltage increases quickly, it decreases slowly. This indicates that secondary discharge does not occur, which is a current in the opposite direction commonly generated by residual charge in NPDBD [9,32]. I t was found to be slightly less than 2 A for both positive and negative discharges when measured through the probe resistor.…”

“…Second, as previously stated, the residual charge accumulated on the dielectric within the discharge space causes specific areas to be discharged more strongly, increasing the likelihood of filamentary discharge [11]. A previous study in air at atmospheric pressure found that the discharge, which was uniform at 100 Hz, became nonuniform as the frequency increased to 1.2 kHz [9]. However, another study in low-pressure air at a low vacuum level yielded a nonuniform discharge when the frequency was reduced from 5 to 1 kHz.…”

“…The top graph in figure 10(a) shows the electron density according to V a at 20 kHz PRR and 20% duty ratio calculated using equation (9). J in equation ( 9) was calculated by dividing I g by the effective discharge area A in table 1, which was calculated using equation (14).…”

“…Recently, scientists are interested in DBD generated by repetition pulses with a fast rise time of nanoseconds to microseconds due to its multiple benefits in manufacturing APNTP [9,10]. It is well known that nanosecond pulse DBD (NPDBD) not only produces a high current peak, electron density, and electron temperature but also can generate discharge evenly at atmospheric pressure with high energy efficiency [11][12][13][14].…”

“…As a result, electrons play an essential role in NPDBD, resulting in a more homogeneous discharge. Third, because the pulse duration time is shorter than the time it takes for discharge instability to occur, NPDBD produces a more uniform and steady discharge [4,9,15,16].…”