Research on the discharge characteristics of different types and micro-structures in the PEF treatment chamber

Pulsed Electric Field (PEF) processing is the application of the high-voltage technology in the biological science and food technology. The main limitations of the technology are the electrical breakdown of the treatment chamber under the repetitive pulsed high-voltage. This paper focuses on the discharge process in the internal treatment chamber, mainly researching on the characteristics of the conductive liquid breakdown in different types and micro-structures of the treatment chamber. It was found that under the same processing conditions, the formation, convergence and rise of bubbles had a great influence on the discharge of the treatment chamber. The different streams of the co-field and cross-field treatment chamber lead to the diversity of the bubble formation process. Size, number and the location of the bubbles determines the initiation and development of the discharge. The discharge process consists of partial discharge, partial breakdown and comprehensive breakdown. The difference between the cross-field and the co-field treatment chamber is that when the discharge breakdown occurs, liquid in the cross-field treatment chamber is heated to higher temperatures while the co-field treatment chamber required more and bigger bubbles and higher conductivity. Therefore, it´s necessary to optimize the design of the subtle features in the internal treatment chamber to lower the probability of partial dielectric breakdown.