汽轮机叶片菌型叶根相控阵超声纵波检测

Phased Array Ultrasonic Longitudinal Wave Detection of Bacterial Blade Root of Steam Turbine Blade

菌型叶根是汽轮机叶片叶根主要形式之一,其缺陷易发于第一齿的弧面位置。针对该位置缺陷的检测,A型超声检测难以区分结构信号与缺陷信号、相控阵超声横波扇形扫查存在耦合不良与移动不便的问题,因此提出相控阵纵波扇形扫查方案。通过仿真软件对模拟缺陷进行检测,根据检测的分辨力和缺陷回波幅值确定相控阵超声纵波检测探头的最优参数;采用最优参数对叶根不同尺寸模拟缺陷进行检测,验证检测方案的精度。对叶根的人工缺陷进行了实验验证,并对服役中的菌型叶片叶根进行了检测,发现了缺陷并通过其它检测方法进行了验证,为菌型叶根的缺陷检测提供了新的检测方案。

Bacterial leaf root is one of the main forms of turbine blade root,and its defects are easy to occur in the arc position of the first tooth.For the detection of defects at this location,it is difficult to distinguish the structure signal from the defect signal by A-type ultrasonic detection,and there are problems of poor coupling and inconvenient movement in the phased-array ultrasonic transverse wave sector sweeping,so a phased-array longitudinal wave sector sweeping scheme is proposed.The optimal parameters of the phased-array ultrasonic longitudinal wave inspection probe are determined according to the resolution of the detection and the amplitude of the defect echo by simulation software.The artificial defects of leaf roots were experimentally verified,and the leaf roots of mycorrhizal leaves in service were inspected,and the defects were found and verified by other inspection methods,which provided a new inspection scheme for the defect detection of mycorrhizal leaf roots.