Magnetic Circuit Design Based on Circumferential Excitation in Oil-Gas Pipeline Magnetic Flux Leakage Detection

In the oil-gas pipeline magnetic flux leakage (MFL) detection, the qualitative and quantitative analysis can be achieved. The circumferential excitation technology is an effective way to detect or size axial direction of defects reliably; Magnetic circuit design has become the key part of this technology to meet the magnetized requirements of circumferential excitation. This paper studies the magnetized section of MFL detector of the oil pipeline. With combination of analytical method and magnetic segmentation method, the Kirchhoff magnetic equation was established with MATLAB to design a magnetic circuit calculation model. Take ¿325×8 pipeline as an example, calculations are carried out to choose suitable geometry parameters and material properties for magnetic circuit design. And simulation by large-scale finite element software ANSYS is carried out to verify the correctness of magnetic circuit design. It has been testified in the results that the design of magnetic circuit has completely met the requirements of circumferential magnetization.