油气管道变形涡流检测线圈探头的有限元仿真分析

Finite element simulation analyses of an eddy current testing coil for inspecting oil and gas pipeline deformation

涡流测距法是油气管道变形检测的一种有效手段,该方法要求电涡流线圈探头的量程较大,以便检测器能够顺利通过管道的变形区域。为提高线圈探头在较远距离上的检测分辨率,利用有限元方法,在保持线圈探头上激励功率不变的条件下,对线圈探头产生磁场的空间分布进行了仿真,并研究了线圈探头的内外径之差、厚度和等效半径对检测分辨率的影响。仿真结果表明:线圈探头的内外径之差增加,其检测分辨率增加;线圈探头的厚度增加,其检测分辨率增加;线圈探头的等效半径增加,其在较远距离下的检测分辨率先增加后减小。试验结果表明:在保持激励功率不变的条件下,增加线圈探头的内外径之差和厚度确实能够提高传感器的检测分辨率和灵敏度,与仿真结果一致。

Eddy current distance measurements are an effective deformation inspection method for oil and gas pipelines.The eddy current probe should have a large measurement range to enable the detector to smoothly pass through the deformed area of the pipeline.The finite element method was used to simulate the magnetic field distribution generated by a coil with a constant input power and to analyze the influences of the difference between the inner and outer coil diameters,the coil thickness and its equivalent radius on the probe detection resolution.The simulation results show that larger inner to outer coil diameter ratio increases the detector resolution and a greater coil thickness increases the detector resolution,while an increased equivalent coil radius first increases the detector resolution over long distances but then reduces the resolution.Tests show that,with the same excitation power,the detection resolution and sensitivity can be improved by increasing the difference between inner and outer diameters and increasing the coil thickness,which agrees with the simulation results.