摘要
油气长输管道是我国重要的能源基础设施,在役管道内外壁缺陷是管道安全运行的严重隐患,需要对其进行定期安全性评估。漏磁检测作为管道无损检测中常见的方法之一,应用非常广泛。基于漏磁检测技术基本原理,采用COMSOL有限元软件,运用周向励磁方法对管道凹坑及类裂纹缺陷的漏磁场分布特征进行了仿真分析。通过改变凹坑和裂纹的几何尺寸和所处位置,得到了不同参数缺陷的漏磁场分布特征曲线。研究结果表明:磁通密度径向分量峰峰值和周向分量峰值随着凹坑半径增加呈非线性增大,随凹坑深度增加呈近线性增大;裂纹的长度、宽度与深度的增加均使漏磁信号非线性增大,且深度对漏磁信号的影响最为明显;靠近永磁体位置的缺陷受背景磁场影响显著,其漏磁信号会异常增大并发生偏移;随着裂纹方向与管道轴向夹角增加,漏磁信号减弱,且当裂纹角度大于一定值后,无法有效检测出漏磁信号。该研究结果对周向励磁方法在工程实践中的应用具有一定的参考价值。
The long distance oil and gas pipeline is an important energy infrastructure in China.The internal and external wall defects of the in-service pipeline are serious hidden dangers for the safe operation of the pipeline,which need to be regularly evaluated.Magnetic flux leakage(MFL)testing is one of the common methods in pipeline nondestructive testing and is widely used.In this paper,based on the basic principle of magnetic flux leakage(MFL)detection technology,COMSOL finite element software and circumferential excitation are used to simulate and analyze the distribution characteristics of magnetic flux leakage in pipe pits and cracks.By changing the geometric size and location of pits and cracks,the magnetic leakage distribution characteristic curves of defects with different parameters were obtained.The results show that the peak-to-peak value of the radial component and the peak value of the circumferential component of the flux density increase non-linearly with the increase of the pit radius and nearly linearly with the increase of the pit depth.With the increase of crack length,width and depth,the MFL signal increases non-linearly,and the depth has the most obvious effect on the MFL signal.The defect close to permanent magnet is obviously affected by background magnetic field,and its magnetic leakage signal will increase abnormally and shift.As the angle between crack direction and pipeline axis increases,the MFL signal weakens,and when the crack angle is greater than a certain value,the MFL signal cannot be effectively detected.
作者
苏林
马雪莉
崔德荣
王天鹰
饶连涛
郝大洋
徐杰
SU Lin;MA Xueli;CUI Derong;WANG Tianying;RAO Liantao;HAO Dayang;XU Jie(PipeChina(Xuzhou)Pipeline Inspection Co.Ltd.,Xuzhou 221008,China;China University of Mining and Technology,Xuzhou 221116,China)
出处
《电焊机》
2022年第3期20-28,共9页
Electric Welding Machine
基金
国家重点研发项目(2018YFB2001204)
国家自然科学基金资助项目(51301197)
江苏省自然科学基金资助项目(BK20130182)
中国石油化工股份有限公司资助项目(318019-2)。
关键词
周向励磁
漏磁检测
凹坑缺陷
裂纹缺陷
有限元模拟
circumferential excitation
magnetic flux leakage detection
pit defect
crack defect
finite element simulation
