油气管道裂纹远场涡流检测的仿真分析

Simulation Analysis on Cracks Detection Based on RFEC in Long-distance Oil and Gas Pipeline

利用有限元分析原理建立远场涡流仿真模型,并对管道裂纹的检测过程进行分析。首先,由麦克斯韦方程组推导出远场涡流的轴对称数学模型,分析磁场在管壁的径向传播特性;再采用局部分析法在ANSYS软件中进行模型优化,减小其计算规模,并估计管道内壁磁场的轴向分布;最后,通过仿真模型得到不同裂纹作用下的检测信号,并讨论了该信号相位与裂纹几何参数,如深度、宽度等之间的对应关系。仿真结果为实际开展远场涡流裂纹检测提供了有效参考。

According to the principles of finite element （FE）, a simulation model of RFEC was established to analyze the detection process for pipeline cracks. First, the axisymmetric mathematic model of RFEC was derived from the Maxwell＇ s equations, through which the radial propagation characteristics of the magnetic field on the surface of the pipeline were analyzed. Then the model of RFEC was optimized by Zoom--In＇ in ANSYS to decrease its size, and the axial distribution of the magnetic field on the internal surface of the pipeline was evaluated. Finally, the detection signals corresponding to different cracks were calculated by the simulation model, and the relations between their phases and the geometric parameters of the cracks, such as depth, width and etc, were discussed. All the simulation results were represented herein and may be as a reference for the practical RFEC inspection of cracks.