孔周裂纹的柔性阵列旋转涡流检测

Flexible array rotating eddy current detection for cracks at edge of holes

针对具有复杂型面的涡轮叶片微小气膜孔周裂纹检测问题,设计制作了新型旋转涡流柔性阵列检测探头,搭建了调幅旋转涡流阵列检测系统,并提出了基于阵列调幅旋转涡流检测信号相位信息的缺陷识别方法。所设计的新型旋转涡流柔性阵列检测探头激励部分采用双层并联电路线圈构型,并使用柔性电路板设计制作,该构型可形成均匀涡流场并减小线圈面积,便于实现检测探头的柔性化和小型化。基于阵列调幅旋转涡流检测信号建立阵列气膜孔的李萨如和极坐标分析图,利用李萨如分析图中的相位信息和极坐标分析图中的幅值信息判断孔周内壁裂纹的信息。通过数值计算和试验,验证了所提出的新型旋转涡流柔性阵列检测探头和孔周背面裂纹识别方法的有效性。

In order to solve the detection problem of crack at the edge of tiny cooling holes in turbine blades with complex profiles,a novel flexible array rotating eddy current probe was designed and fabricated in this paper.A modulated rotating eddy current array detection system was built,and a defect identification method based on the phase information of the array modulated rotating eddy current detection signal was proposed.The excitation part of the novel flexible array rotating eddy current probe adopted double-layer parallel circuit coil configuration and was designed and fabricated using flexible circuit board printing technology.This configuration can create a uniform eddy current field and reduce the coil area,facilitating the flexibility and miniaturization of the detection probe.Based on the array modulation rotating eddy current detection signal,a Lissajous and polar coordinate analysis diagram of the array cooling holes was established to judge the information of inner wall cracks at the edge of cooling hole based on the phase information in the Lissajous analysis diagram and the amplitude information in the polar coordinate analysis diagram.The effectiveness of the proposed novel flexible array rotating eddy current probe and the defect identification method for inner wall cracks was validated through numerical calculations and experiments.