对锅炉管弯头进行涡流检测时,弯头复杂的曲面结构会对检测结果的准确性产生影响, 故分析弯头曲面对探头阻抗的影响具有重要意义。通过建立放置式涡流探头检测不锈钢弯头的ANSYS有限元模型, 分析了弯头弯曲半径及周向检测位置的变化对探头反射阻抗的影响, 并进行了试验验证。结果表明: 弯曲半径增大时, 反射阻抗幅值的变化量增大, 相位则减小; 探头从弯头内侧往外侧移动时, 反射阻抗幅值的变化量逐渐减小, 而相位则增大。

The complex structure of elbow surface is the main difficulty which hampers eddy current technique being conducted on boiler tube elbow. Therefore, in order to improve the detection accuracy, it is of great significance to study the influence of the elbow surface on probe’s impedance. In this paper, the finite element model of a pancake probe-coil over a stainless steel tube elbow was established. Influences of the variations of the pipe’s curvature radius and the probe′s circumferential detecting position on the probe’s reflected impedance were respectively studied. Also, an experiment validation of the simulation was conducted. The results are as follows: (i) as the radius of curvature increases, the variation of the reflected impedance amplitude increases but the impedance phase decreases. (ii) as the probe is moved from the inner side of the elbow to the outer side, the variation of the reflected impedance amplitude decreases but the impedance phase increases.