高压水下湿法焊接电弧等离子体介质击穿机制  

Mechanism on dielectric breakdown of arc plasma in high pressure underwater wet welding

作　　者：李志刚 魏成法 刘德俊 杨翔 LI Zhigang;WEI Chengfa;LIU Dejun;YANG Xiang(Key Laboratory of Transportation Tools and Equipment,Ministry of Education,East China Jiaotong University,Nanchang,330013,China)

机构地区：[1]华东交通大学,载运工具与装备教育部重点实验室,南昌330013

出　　处：《焊接学报》2023年第8期49-56,I0006,共9页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(52265046)。

摘　　要：为研究深水湿法焊接电弧等离子体介质击穿机制,建立了高压水下湿法焊接试验平台,获取40 m水深电弧引弧阶段光谱图,基于PIC-MCC方法建立40 m水深湿法焊接电弧击穿放电三维数值模型并对其进行分析,将光谱诊断电弧等离子体温度、电子数密度和数值模型分析得到的结果进行对比,验证了模型的合理性与正确性.根据电弧光谱得到的电弧等离子体的主成分,从微观粒子角度对高压水下湿法焊接电弧等离子体动态演变过程展开研究,获得等离子体动态分布、粒子数目、电弧等离子体温度及电子数密度变化.结果表明,电子与背景成分水分子发生电离碰撞主要生成H^(+),OH^(+)和O^(+),且OH^(+)数目增长速度最快,H^(+)次之,O^(+)最后,在粒子数目上OH^(+)远远大于H^(+)和O^(+)数目;电子与背景气体碰撞过程中发生了能量转移,运动到极板介质层的电子动能减小,电子与极板介质层电离碰撞反应弱化,直至达到饱和.In order to study the mechanism of arc plasma breakdown in deep water wet welding,a high-pressure underwater wet welding experimental platform was established.Spectral maps of the arc initiation stage at a depth of 40 m were obtained,and a three-dimensional numerical model of arc breakdown discharge at a depth of 40 m was established based on the PIC-MCC method and analyzed.The results of spectral diagnosis arc plasma temperature,electron number density and numerical model analysis were compared,and the rationality and correctness of the model were verified.Based on the main components of the arc plasma obtained from the arc spectroscopy,a study was conducted on the dynamic evolution process of the arc plasma in high-pressure underwater wet welding from the perspective of microscopic particles,and the dynamic distribution,number of particles,temperature and electron number density of the arc plasma were obtained.The results showed that H^(+),OH^(+)and O^(+)were mainly generated by the ionization collision between the electron and the background component water molecule,and the number of OH^(+)increased fastest,followed by H^(+),and O^(+)last,the number of OH^(+)particles was far greater than the number of H^(+)and O^(+)particles;During the collision between electrons and background gas,the energy shifted,and the kinetic energy of electrons moving to the dielectric layer of the electrode decreased,the ionization collision reaction between electrons and the dielectric layer of the electrode weakened until saturation was reached.

关 键 词：水下湿法焊接电弧 微观粒子 动态演变 介质击穿机制 

分 类 号：TG456.5[金属学及工艺—焊接]