水轮机空化的声发射信号多尺度特征提取及其演变规律研究

项目名称： 水轮机空化的声发射信号多尺度特征提取及其演变规律研究

项目编号： No.51309034

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 水利工程

项目作者： 刘忠

作者单位： 长沙理工大学

项目金额： 25万元

中文摘要： 水轮机空化机理的复杂性使其状态监测与故障诊断问题一直是国内外尚未解决的科学难题之一。已证实随空化产生的气泡群溃灭是一种典型的频段远高于20kHz的声发射（Acoustic Emission，AE）信号源。然而，其随空化状态变化的本质特性还未被揭示和充分利用。本项目以不同工况下水轮机空化所致的AE信号为研究对象，对空化AE信号的多尺度特征及其随空化演变的规律进行科学研究。具体内容包括：理论分析水轮机空化AE信号在生成、传播和采集等环节的影响因素；试验获取不同空化状态下的AE信号数据；分别基于小波熵和Hilbert-Huang变换方法对AE信号进行降噪提纯和多尺度特征提取；构建多维AE信号特征矢量-空化状态对，反映AE信号特征与水轮机空化发展状态的对应关系。本项目的成功实施将有助于从高频声学角度揭示水轮机空化发展演变规律，为实现水轮机空化的在线监测与智能诊断提供有力的理论依据和技术支持。

中文关键词： 水轮机；空化；声发射；特征提取；规律

英文摘要： The scientific problem of condition monitoring and fault diagnosis of hydraulic turbine cavitations around the world remains unsolved due to the complicated cavitations mechanisms. It's known that acoustic emission (AE) signal is an external symptom for cavitations with high frequency bands above 20 kHz. However, its characteristics varying with cavitation states have not been revealed and further fully used. The AE signals induced by hydraulic turbine cavitations under different conditions are taken as the research object in this project. Their multi-scale characteristic parameters and change rules with cavitation states are studied in a scientific manner. The project consists of the following parts. (i) The factors influencing the AE signals during their growth, transmission and acquisition are analyzed qualitatively and theoretically. (ii) The AE signals under different cavitation states in a model hydraulic turbine rig are collected by the cavitation experiments. (iii) The AE signals are denoised with the wavelet entropy method and their multi-scale features are extracted with Hilbert-Huang Transform method. (iv) The multi-dimensional couples of AE signal characteristic vector with cavitation state are established, which reflect the varying relationships. The successful implementation of this project will he

英文关键词： hydraulic turbine；cavitation；acoustic emission；feature extraction；rules