摘要
为研究剥离涂层下含缺陷的金属管道缝隙腐蚀问题,建立了一个充分考虑缝隙内溶液传质过程、电位梯度变化和电中性原则等影响的二维数学模型。利用数值模拟研究了施加阴极保护对含缺陷金属管道腐蚀行为的影响,分析了瞬态条件下缺陷内溶液的溶解氧含量、离子浓度和电导率随时间的变化。数值模拟结果表明:在35 h前阴极保护电位无法完全保护缝隙内的缺陷,且缺陷处的电位差随着与缝口距离增加逐渐减小;在缺陷处电迁移传质和溶液浓度梯度影响离子的扩散,使阳离子向缺陷内、阴离子向缺陷外运动;还原反应导致溶液的电导率随时间的推移而增大,但随缝隙深度增加而降低,在缺陷底部的电导率略高于缺陷口的电导率。
To study the crevice corrosion of metal pipes with defects under disbonded coatings,a two-dimensional mathematical model was established,which fully considered the effects of mass transfer process of solution in the crevice,potential gradient change and the principle of electric neutrality.The influence of cathodic protection on the corrosion behavior of metal pipelines containing defects was studied by numerical simula-tion,and the evolution of dissolved oxygen concentration,ion concentration and conductivity of solution in defects with time under transient condi-tions were analyzed.The numerical simulation results show that the cathodic protection potential could not completely protect the defects in the crevice before 35 h,the potential difference at the defects gradually decreased with the increase of the distance from the crevice;in the defect area,due to the influence of electromigration mass transfer and solution concentration gradient on the diffusion of ions,cations move towards the defect interior and anions towards the defect exterior;the reduction reaction causes the conductivity of the solution to increase with time,but to decrease with the increase of the crevice depth.The conductivity at the bottom of the defect is slightly higher than that at the defect mouth.
作者
李雷
孙东旭
柴玉莹
谢飞
吴明
LI Lei;SUN Dongxu;CHAI Yuying;XIE Fei;WU Ming(College of Petroleum and Natural Gas Engineering,Liaoning Petrochemical University,Fushun 113001,Liaoning,China;Shenyang Blower Works(Group)Co.,Ltd.,Shenyang 110869,China)
出处
《材料导报》
北大核心
2025年第5期231-239,共9页
Materials Reports
基金
国家自然科学基金青年基金(52404058)
辽宁省教育厅基本科研项目面上项目(LJKMZ20220734)
辽宁省博士科研启动基金(2023-BS-187)。
关键词
缝隙腐蚀
阴极保护
缺陷
瞬态数值模拟
crevice corrosion
cathodic protection
defect
transient numerical simulation
作者简介
李雷,辽宁石油化工大学硕士研究生,主要研究方向为管线钢腐蚀与防护;通信作者:孙东旭,博士,副教授,硕士研究生导师。主要从事油气管道完整性管理、管线钢腐蚀与防护和LNG储运工艺等方面的研究dx_sun@sina.cn。
