Effect of water on gliding arc discharge fluctuation

The effect of water on the fluctuation of atmospheric gliding arc discharge has been investigated through the undulations of arc voltage signals by using the fast Fourier transform (FFT) and the short-time Fourier transform (STFT). Two kinds of fluctuation mode can be observed in the gliding arc discharge: sawtooth fluctuation and continuous breakdown fluctuation. The voltage signals and their spectra obtained by FFT and STFT exhibit the fundamental frequency of 100 Hz, which originates from the inherent characteristic of the ac power supply. Comparative investigations of time-frequency characteristics of arc voltage signals under different working conditions indicate that adding water vapor and water spray can reduce the fluctuation of the gliding arc plasma and strengthen the stable state of the arc. Additionally, the arc voltage characteristics indicate that adding water vapor increases the breakdown voltage and decreases the arc length, whereas water spray decreases the breakdown voltage and makes discharging easy. Copyright (c) EPLA, 2008.