Pulsed arc discharge in water: mechanism of current conduction and pressure wave formations

Abstract

Pulsed arc electrohydraulic discharge in water was used for water treatments and removal of Zebra mussels in lake or sea water. In this work, the current conduction mechanism and the formation of pressure waves were experimentally investigated. Pulsed arc discharges were generated by a spark gap type power supply (0.3-1 kJ) with rod-to-rod type electrodes in pure and tap waters and applied voltage, discharge current and pressure waveforms were measured. Optical emission was measured by an optical spectrometer (200 to 800 nm). The results show that: (1) A cavitation zone was formed immediately after the formation of discharge generated pressure waves; (2) strong UV lights as well as OH radical related emissions were observed; (3) the effect of water conductivity significantly influenced current waveform only at the initial phase of discharge. Based on experimental results, the mechanism of current conduction and pressure wave formation was proposed.