基于多向交流电位降技术的管道裂纹腐蚀检测方法
Crack Corrosion of Pipeline Detection Based on Multidirectional Alternating Current Potential Drop Technology
作者：李文洋(四川大学 机械工程学院, 四川 成都 610065)；甘芳吉(四川大学 机械工程学院, 四川 成都 610065)；周永杰(青海师范大学 物理与电子信息工程学院, 青海 西宁 810016)；何晓明(青海师范大学 物理与电子信息工程学院, 青海 西宁 810016)
Author：LI Wenyang(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)；GAN Fangji(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)；ZHOU Yongjie(College of Physics andElectronic Info.Eng., Qinghai Normal Univ., Xining 810016, China)；HE Xiaoming(College of Physics andElectronic Info.Eng., Qinghai Normal Univ., Xining 810016, China)
收稿日期：2018-07-16 年卷（期）页码：2019,51(5):165-169
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：交流电位降技术;趋肤效应;多向电流;缺陷检测
Key words：AC potential drop technology;skin effect;multidirectional current;crack detection
基金项目：国家自然科学基金项目（51704199）；中央高校基本科研业务费项目（2017SCU12027）；青海省科技计划基础研究计划项目（2018-ZJ-719）
中文摘要
管道长期输送含有大量腐蚀成分的原油和天然气，会严重腐蚀管道内壁，产生裂纹缺陷，降低油气管道的工作性能。交流电位降技术可用于检测油气管道的内腐蚀缺陷。该方法的核心是根据交流电流在金属构件内的分布满足趋肤效应，不同的裂纹缺陷对渗透电流场分布存在不同影响，进而改变测量电压值，因此可以通过检测电压值的变化来检测腐蚀情况。但是目前交流电位降技术只能检测固定方向的裂纹缺陷，对位置随机的裂纹求解准确度低，尤其是电极连线方向与裂纹方向夹角小于45°的缺陷不能求解。为了提高随机裂纹的检测精度，提出了多向交流电位降法，即向被测管道施加不同方向的激励电流，使裂纹方向与电流极连线方向的夹角（余角）范围从0°～90.0°变为67.5°～90.0°。仿真和实验结果表明，裂纹方向与电流极连线方向的夹角越接近90°，测得的电压与原始电压的比值越大，此时的电压比值随裂纹深度变化越接近指数分布。所提出的多向交流电位降法能有效地扩大裂纹检测范围，提高随机裂纹的检测精度，为更好地监测输气管道状况，维护管道运输安全提供了新的技术手段。
英文摘要
Pipelines will be seriously corroded by crude oil and natural gas in the long-term transportation. AC potential drop technology can be used to monitor the inner wall of oil or gas pipelines. The core of the method is based on the distribution of alternating current meeting with skin effect in the metal component. Different crack defects have different effects on the distribution of osmotic current field and change the measured voltage value. Therefore, corrosion can be monitored by monitoring the change of voltage value. However, this monitoring method can only monitor the crack defects in the fixed direction, and the accuracy of solving a crack at random position is low. The Angle between the direction of electrode wire and crack should be greater than 45°. An innovative method was proposed called multidirectional AC potential drop, which made the angle between the direction of crack and electrode wire from 0°～90.0° to 67.5°～90.0°. The simulation in finite element analysis software and experimental results showed that the values of the ratio of voltage were exponential along with crack depths by using multidirectional AC potential drop technology. The proposed method can more accurately monitor the random crack corrosion, which enriches and develops the inspection of pipelines.
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