Temporal evolution characteristics of the excited species in a pulsed needle-water discharge: effect of voltage and frequency

Abstract

Transient spark discharge has a broad application prospect due to its excellent performance in generating reactive oxygen species, but there is currently limited research on the transient excited species which are the important precursors for the formation of these species. This paper obtained a transient spark discharge with a needle-water electrode configuration, and then developed an optical detection system based on photomultiplier to measure the temporal evolution of four excited species. It is observed that N2 (C) is produced mainly in the streamer phase while H (n=3), O (3p), and OH (A) are produced mainly in the spark phase, which is resulted from the difference in threshold energy and pathway for generating different species. To investigate the variation mechanism of peak time and peak intensity during the evolution process, the gas temperature T g, electron density n e, and electron excitation temperature T exc were calculated by using the optical emission spectroscopy under different pulse voltage and pulse repetition frequency conditions. The results indicate that the discharge conditions influence the physical parameters of T g, n e, and T exc as well as the output voltage waveform, and then they jointly determine the evolution characteristics of excited species. These insights contribute to understand the characteristics of excited species which affect the formation of reactive species by influencing the chemical chain reaction in the transient spark discharge.

DBD-like and electrolytic regimes in pulsed and AC driven discharges in contact with water

“…This discharge and the accompanying current signal last during most of the pulse, approximately 1.4 µs. A similar observation was also reported in [36] and [22]. Here we have to distinguish between the different behavior of positive and negative operation, i.e.…”

“…The large range of different aspects investigated on plasmawater interaction in other works [7,[14][15][16][17][18][19][20][21][22] demonstrates the complexity of this topic. Therefore, knowledge on the interdependency of plasma and water properties is of importance for a better understanding of underlying processes.…”

Fast breakdown process and characteristics diagnosis of nanosecond pin–pin discharge

“…Firstly, the temperatures during the two discharge phases are calculated in figure 9. The experimental spectrum of the SPS of N 2 captured in the streamer phase below a gate width of 5 ns is compared with the simulated spectrum in SPECAIR software to obtain the rotational temperature and vibrational temperature [36,37]. The experimental spectrum fits well with the simulated spectrum as shown in figure 9(a); thus, a rotational temperature of 500 K and a vibrational temperature of 2150 K during the streamer phase are obtained.…”

Magnetic field improves ozone production in an atmospheric pressure surface dielectric barrier discharge: understanding the physico-chemical mechanism behind low energy consumption

“…Thus, the cumulative thermal effect and positive feedback effect of thermal instability led to the rise in T g and ε . 56,57 Additionally, Guo et al reported that the memory effect of the residual charge in the discharge space would be enhanced with increasing frequency. 58 This also improved the total electric field which contributed to the rise in ε and T g .…”