均匀电场重频脉冲作用下的水中气泡击穿  

Gas Bubbles Breakdown in Water Under Repetitive Pulsed Uniform Electric Field

作　　者：张若兵 王致远 陈志浩 ZHANG Ruobing;WANG Zhiyuan;CHEN Zhihao(Tsinghua Shenzhen International Graduate School,Shenzhen 518055,China)

机构地区：[1]清华大学深圳国际研究生院,深圳518055

出　　处：《高电压技术》2021年第1期331-337,共7页High Voltage Engineering

基　　金：国家自然科学基金(51677105)。

摘　　要：均匀电场重频脉冲作用下处理室放电问题是高压脉冲电场(pulsed electric field,PEF)技术遇到的难题。目前现有水中空气泡的击穿研究无法说明这种平均电场强度较低(<70 kV/cm)的情况下的击穿现象。为了解决这一问题,设计了金属平板电极与水溶液电极间的气体击穿实验,利用等效实验研究了有水溶液电极的大气压下短间隙(<1 cm)的气体击穿现象。通过实验得到了液体做电极的空气气隙的击穿电压,证明了阴极种类以及重频脉冲参数对击穿电压的影响,得到了均匀电场作用下水溶液中气泡的内部电场与气泡形状参数和气液介电常数的关系式。研究结果表明PEF处理室的完全击穿是由水溶液中的气泡击穿所引起的,受阴极二次电子发射系数γ的影响,并预测了水中空气泡击穿场强,为合理设计PEF处理室提出重要参考依据。Breakdown caused by bubbles is a critical technical problem for the application of PEF(Pulsed Electric Field). At present, theories about gas bubbles breakdown under water can not explain the breakdown phenomenon of uniform electric field under 70 kV/cm. In order to solve this problem, the gas breakdown experiments between the metal plate electrode and the aqueous electrode are designed in this paper. The breakdown voltage of the air gap with the liquid electrode is obtained, which proves the influences of the cathode types and the repetition frequency pulse parameters on it. The gas-breakdown phenomenon of short-gap with aqueous electrode(less than 1 cm) at atmospheric pressure was studied by equivalent experiments. The relationship between the internal electric field of bubble and the bubble shape factor as well as gas-liquid dielectric constant under uniform electric field was obtained. According to the research above, it is considered that the complete breakdown of the PEF treatment chamber is caused by the bubble breakdown in the aqueous solution, which is affected by the secondary electron emission coefficient γ of the cathode. The breakdown field strength of bubbles in water is predicted. This work presents vital references for designing PEF treatment chambers.

关 键 词：高压脉冲电场 重频脉冲 气泡动力学 PEF处理室 气体放电 

分 类 号：TS205[轻工技术与工程—食品科学]