Gas-water two-phase discharge phenomenon in PEF chamber for water treatment

Abstract

Pulsed Electric Field treatment is a critical technology in waste water treatment and sterilization. However, the discharge of the treatment chamber that causes the damage of pulse generators is one of the main technical issues of its applications. Bubbles under water are the most vulnerable sections and could cause breakdown since it is too difficult to generate discharge in the bulk of water under microsecond-pulse and relatively low electric field(<70kV/cm). Uniform discharging images of gas bubbles under water are captured. The influence of γ approach on breakdown in short gas gap (under 1cm) with water electrode under atmospheric pressure is confirmed. The influence of conductivity of aqueous solution and the repetitive frequency of voltage pulses is discussed. It can be confirmed that the breakdown phenomenon of the PEF treatment chamber is mainly caused by air bubbles, which are generated by Joule heat process as well as cavitation and then discharge under the metal cathode. This work presents vital references for improving the design of PEF treatment chambers.