中文摘要：

针对天然气管道阀门运行过程中承受较高压力易发生内漏且内漏不易被发现的问题,设计了基于声发射理论的阀门内漏检测系统,并在基于LabVIEW图形化编程语言基础上开发相应的检测分析软件。应用该检测系统对某内漏阀门进行室内检测试验研究。试验结果表明：4层小波分解后的声发射信号时域A4,D4,D1频带均方根值,频域A4,D4峰值与阀门内漏程度有良好的相关性,该系统可以有效地对运行过程中天然气管道阀门内漏程度进行无损检测与识别。

英文摘要：

Aiming at the problem of inner leakage of valve for natural gas pipeline under high pressure during operation and difficult to be found, an inner leakage detection system based on acoustic emission theory for valve is designed, and the corresponding testing and analysis software is developed under LabVIEW graphical programming language. A valve with inner leakage is tested with applying this detection system. The experimental results demonstrate that RMS （A4, D4 and D1 band） of time domination and peak value （A4 and D4） of frequency domain with 4 layer wavelet decomposition has a good correlation with the degree of valve inner leakage, and the designed system is effective to detect and identify valve inner leakage for natural gas pipeline under operation.