摘要
探究水轮机空化诱导的声发射信号随空化状态的变化规律对监测空化具有重要意义。为解决声发射信号携带噪声和特征提取困难的问题,本文建立一种基于自适应迭代滤波分解-奇异谱分析联合降噪和固有时间尺度分解结合特征参数的特征提取方法。首先,采用自适应迭代滤波分解结合相关系数对声发射信号初步降噪,滤除明显噪声分量,重构剩余分量并通过奇异谱分析进一步降噪,将所得信号与趋势分量相加,完成整个降噪过程。然后,对降噪后信号进行固有时间尺度分解,筛选出有效分量,计算其绝对能量和相对能量熵。最后,分析它们随空化系数变化的规律。研究结果表明,绝对能量和相对能量熵随空化系数的变化具有明显的规律性,均能反映水轮机空化的发展状况。
Understanding the acoustic emission signals from hydraulic turbines under flow cavitation and its variations with cavitation intensity is essential for monitoring cavitation.To overcome the difficulty in feature extraction from acoustic signals due to noise pollution,this paper develops a feature extraction method based on noise reduction through adaptive local iterative filtering and singular spectrum analysis,and on intrinsic time scale decomposition combined with feature parameters.First,an acoustic signal is initially denoised using the adaptive local iterative filtering combined with correlation coefficients to filter out evident noise components;the remaining components are reconstructed and further denoised via singular spectrum analysis.Adding the resulting signals to the trend component completes the whole noise reduction.Then,an intrinsic time scale decomposition algorithm is used to decompose the noise-reduced signal,screen out its effective components,and calculate their absolute energy and relative energy entropy.Finally,their variation trends with the cavitation coefficient are examined.The results show the variations in absolute energy and relative energy entropy with the cavitation coefficient manifest better regularity,offering an effective indicator of the developing status of hydraulic turbine cavitation.
作者
刘忠
王文豪
邹淑云
李显伟
周泽华
LIU Zhong;WANG Wenhao;ZOU Shuyun;LI Xianwei;ZHOU Zehua(School of Energy and Power Engineering,Changsha University of Science and Technology,Changsha 410114,China)
出处
《水力发电学报》
CSCD
北大核心
2022年第12期145-152,共8页
Journal of Hydroelectric Engineering
基金
国家自然科学基金资助项目(52079011)
湖南省研究生科研创新项目(CX20220927)。
关键词
水轮机
空化
声发射
SSA算法
降噪
ITD算法
hydraulic turbine
cavitation
acoustic emission
SSA algorithm
noise reduction
ITD algorithm
作者简介
刘忠(1978-),男,副教授.E-mail:drliuzhong@csust.edu.cn。
