材料期刊网

目的：外加电流阴极保护技术逐渐应用于船舶和海洋结构物防腐领域，但随之而来的杂散电流很可能使平台附近的海底管道本身或者其牺牲阳极阴极保护系统产生电化学腐蚀，缩短海底管道使用寿命，甚至破坏管道本身结构而造成严重的生产事故，因此需要预测外加电流阴极保护系统对附近海底管道及其牺牲阳极阴极保护系统可能造成的不利影响。方法提出一种基于边界元法的预测海底管道杂散电流影响的数值模拟方法，建立包括域内控制方程和对应的边界条件的数学模型，可以计算得到海底管道受杂散电流影响区域的位置和范围，并且得到受影响区域表面保护电位的分布情况。结果通过实验室海底管道模型杂散电流试验测量结果与数值模拟结果进行比较，验证该方法预测海底管道杂散电流影响的准确性，数值模拟仿真结果与试验测量结果最大误差百分比约为1.7%，平均误差百分比小于0.2%。数值模拟计算结果准确地预测了海底管道模型表面保护电位分布情况，预测了导管架平台模型外加电流阴极保护系统对海底管道模型杂散电流的影响情况。结论使用的边界元阴极保护数值模拟技术可以准确预测海底管道杂散电流的影响情况，为海底管道杂散电流影响预测研究提供了有力工具。

ABSTRACT:Objective Impressed current cathodic protection technology is used in the field of ship and marine structures increasingly, but the attendant stray currents is likely to lead subsea pipeline itself or its sacrificial anode cathodic protection system near the platform to suffer from electrochemical corrosion, which can shorten the submarine pipeline’s operation life, and even destroy the structure of the pipeline and cause serious accidents. Therefore, it is necessary to predict the adverse influ-ence which impressed current cathodic protection system may cause on subsea pipelines and its sacrificial anode cathodic pro-tection system.Methods This paper presented a numerical simulation method based on the boundary element method to predict the influence of stray current on submarine pipelines. The mathematical model including the control equation and the corres-ponding boundary conditions was established to calculate the position and range of protection potential of the submarine pipe- line which was influenced by the stray current, and the distribution of surface protection potential in the affected area could also be obtained.ResultsBy comparing the results of model experiment in laboratory and numerical simulation,the accuracy of the method for predicting the influence of stray currents on subsea pipeline was validated. The largest percentage error of numerical simulation results compared to experimental measurements was about 1.7%, and the average of percentage error was less than 0.2%, consequently the numerical simulation results accurately predicted the protection potential distribution of the subsea pipe-line model, in other words, the numerical simulation results predicted the influence of impressed current cathodic protection system of the jacket platform on subsea pipeline model by stray current.ConclusionThe boundary element cathodic protection numerical simulation software used in this study could accurately predict the influence of stray current on the potential distribu-tion of submarine pipeline, and it could be a powerful tool for study on prediction of influence of stray current on the potential distribution of submarine pipeline.