载荷作用下管道漏磁内检测信号定量化研究

Quantization of pipeline magnetic flux leakage detection signal under load

管道漏磁内检测技术是国际公认的长输油气管道安全维护的最有效方法。为解决载荷作用下长输油气管道漏磁内检测信号定量化问题,本文基于J-A理论建立了改进的三维磁荷数学模型,分析了管道缺陷在内压作用下的磁力学效应对漏磁信号的影响规律,研究了外部载荷作用下缺陷尺寸对漏磁信号影响规律,并通过系统的实验验证了理论模型的正确性。研究结果表明:管道内压增加,材料磁化强度减小,漏磁信号径向分量和轴向分量呈指数函数下降规律;漏磁信号径向分量峰值和轴向分量极大值随着缺陷深度增加而增加,增长率逐渐降低,特征值分别变化6.5%和14.7%;径向分量峰值增长率随长度增加而逐渐降低,轴向极大值线性减小,特征值分别变化21.0%和36.8%,轴向分量对缺陷深度和长度变化更敏感。

Pipeline magnetic flux leakage internal detection technology is internationally recognized as the most effective method for safety maintenance of long-distance oil and gas pipelines.To solve the problem of quantifying the internal detection signal of magnetic flux leakage in long-distance oil and gas pipelines under load,an improved three-dimensional magnetic charge mathematical model is formulated,which is based on the J-A theory.The influence of the magnetomechanical influence of pipeline defects on the magnetic flux leakage signal under internal pressure is analyzed.The influence law of the defect size on the magnetic flux leakage signal under the action of external load is studied,and the correctness of the theoretical model is evaluated through systematic experiments.Research results show that the internal pressure of the pipeline increases,the magnetization of the material decreases,and the radial and axial components of the magnetic flux leakage signal decrease exponentially.The peak value of the radial component and the maximum axial component of the magnetic flux leakage signal increase with the depth of the defect.The growth rate gradually decreases,and the eigenvalue changes by 6.5%and 14.7%,respectively.The peak growth rate of the radial component gradually decreases with the increase in length,and the axial maximum value decreases linearly.The eigenvalue changes by 21.0%and 36.8%,respectively.The axial component is more sensitive to changes in defect depth and length.