声发射技术在水轮机叶片裂纹监测和诊断中的应用  

Application of AE Technology in Monitoring and Diagnosing Cracks in Turbine Blades

作　　者：朱相源 张学志 刘吉营 江伟 刘志利 Zhu Xiangyuan;Zhang Xuezhi;Liu Jiying;Jiang Wei;Liu Zhili(Shandong Jianzhu University,Jinan 250101,China;Northwest A&F University,Xianyang,Shaanxi 712100,China;Huadian Electric Power Research Institute Co.,Ltd.,Hangzhou 310030,China)

机构地区：[1]山东建筑大学,济南250101 [2]西北农林科技大学,陕西咸阳712100 [3]华电电力科学研究院有限公司,杭州310030

出　　处：《机电工程技术》2024年第1期14-18,共5页Mechanical & Electrical Engineering Technology

基　　金：国家自然科学基金资助项目(51809218);山东省自然科学基金资助项目(ZR2021QE258)。

摘　　要：水轮机转轮叶片裂纹严重影响电站运行的安全稳定性。然而,裂纹所产生的噪声信号十分微弱,在实际运行时易被强背景噪声淹没。为了更好地监测叶片裂纹产生的噪声信号,采用声发射(AE)技术进行信号采集监测,同时使用小波阈值降噪方法对信号进行提取分析。研究结果表明:在水轮机停机时,声发射技术监测信号的幅值范围为10~60 mV的断铅信号;AE信号的主要频率在64~128 kHz,噪声信号主要集中在第4和第5个小波系数中;采用AE参数可以准确定位产生裂纹的叶片;当传感器安装在转轮叶片正上方时,AE信号接收所需的距离和时间最短,提取到的结果更精确;采用AE技术可以及时发现叶片裂纹的初期状况,便于尽早采取合理的加固与补修措施。声发射监测技术对电站运行的安全稳定性具有重要的现实意义和经济价值。Cracks in the turbine runner blades seriously affects the safe and stable operation of the power station,However,the noise signal generated by the crack is very weak and is easily overwhelmed by strong background noise during actual operation.In order to better monitor the signal when the blade crack is generated,the acoustic emission(AE)technology is used to collect the signal,and then the wavelet threshold noise reduction method is used to extract the acquired signal.Research results show that when the turbine is shut down,the amplitude of the signal monitored by AE technology ranges from 10 to 60 mV;the main frequency of the AE signal is between 64 and 128 kHz,and the noise signal is mainly concentrated in the 4th and 5th wavelet coefficients;the cracked blade can be identified through AE parameters;and by mounting the sensor directly above the runner blades,the distance and time required to receive the AE signal are the shortest,which can extract a more accurate result.Moreover,when using AE technology,the condition of the runner blade cracks can be detected in time at the early stage,so that reasonable reinforcement and repair measures can be taken as soon as possible.This is of great practical significance for the safe and stable operation and long-term benefits of hydropower stations,and has important engineering significance and academic value for the promotion and development of AE technology.

关 键 词：声发射技术 叶片裂纹 裂纹信号 小波阈值降噪方法 

分 类 号：TK703.8[动力工程及工程热物理—流体机械及工程] TP277[自动化与计算机技术—检测技术与自动化装置]