The exploration of discharge efficiency and uniformity improvement with pre-ionized bipolar pulse method in DBD device

Abstract

An exploration of discharge efficiency and uniformity improvement by using pre-ionized bipolar pulse method in dielectric barrier discharge (DBD) device under atmospheric pressure is conducted. Through utilizing the pre-ionized charged particles on the dielectric surface, the amplitude of the applied pulses for sustaining discharge can be significantly decreased. By analyzing the influence of “built-in” electric field from surface charges on discharge efficiency and uniformity, a scheme of pre-ionized bipolar pulse method is proposed. Since the property of “built-in” field is closely dependent with pre-ionized pulse parameters, such as amplitude, pulse number, and polarity, the discharge uniformity and efficiency under different combinations of pre-ionized pulse parameters are investigated. According to experimental results, the discharge efficiency of the proposed method is increased by 11.8% and 17.4%, and the production efficiency of active species of N2(C3Πu→ B3Πg) is increased by 10.4% and 89.5% compared with a conventional bipolar pulse and positive pulse method, respectively, in ambient air. Moreover, the uniformity of DBD discharge is improved, and the maximum intensity difference between discharge regions is decreased from ∼20% to ∼5% compared with the one driven by the conventional positive pulse.

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

“…The coefficient a is the inverse of the capacitances C t and C p , and V g is close to zero when the discharge is extinguished [41]. In the case of other researchers who used the same method to obtain V d , the coefficient a was calculated using the voltage distribution law while accounting for the measured capacitance, as shown in equation ( 7) [42,43]. Finally, the air gap voltage can be obtained using equation (8).…”

“…When looking at V d , the voltage across the dielectric layer, the residual charge generated by the previous discharge forms a wall voltage, resulting in a voltage of approximately −3.8 kV. This is called the preionization effect [43]. Following that, as the discharge starts, all the charges accumulated by the previous discharge move, and as the discharge phenomenon continues, charges of opposite polarity can be seen accumulating.…”

“…Figures 7(a), (c) and (e) present graphs showing the Lissajous curve and capacitance under the standard application conditions of 15 kV, 20 kHz, and 20%, when the other two conditions are fixed and only one electrical condition is altered. Figures 7(b), (d) and (f) present graphs showing the power consumption, charge, and wall voltage calculated from figures 7(a), (c) and (e) using equations ( 13)-( 17) [36,42,43,51]. Figure 7(a) shows the characteristics of the Lissajous curve as a function of applied voltage.…”

“…This result is also consistent with the phenomenon shown in figure 6(a), which is caused by a greater amount of residual charge from the previous discharge. The residual charge value is visible even when the applied voltage is 0 kV (when no external power source is present) [42,43]. Additionally, a steep slope of the Lissajous curve indicates that discharge is still ongoing, whereas a gentle slope indicates that discharge has ended [52].…”

Effect of rotating a dielectric barrier on discharge energy and uniformity in an atmospheric pressure air DBD

“…To improve the uniformity of plasma discharge, Somekawa et al employ a voltage of opposite polarity to clear the memory effects of surface charges [27]. Fan et al found that the discharge efficiency and uniformity can be enhanced by utilizing pre-ionized charged particles on the dielectric surface [28]. Additionally, the introduction of airflow can influence the distribution of residual space particles and therefore change the location of subsequent discharges [29,30].…”