基于声发射的天然气管道球阀内漏检测

Detection of internal leakage of ball valves in gas pipeline based on acoustic emission theory

通过理论分析,建立了阀门内漏过程中气体体积泄漏率与声发射信号特征参数均方根(AERMS)的函数关系,探讨了球阀在密封圈损伤状态下和泄漏率下的声学特征。应用基于小波包理论的信号分析与处理方法对内漏信号进行能量分析,结果表明:当密封圈为单一损伤时,能量主要分布频率范围为12.5～62.5kHz,声发射信号AERMS与球阀气体体积内漏率成双对数关系,可以利用声发射检测天然气管道阀门是否发生内漏并估算其体积泄漏率。

Through theoretical analysis, the functional relationship between volumetric leaking rate of gas and root mean square of acoustic emission （AERMS） during internal leakage of valve is established. In addition, acoustic features of ball valve in case of o-ring damages and under specific leaking rates are investigated. Energy analyses is made for internal leakage signals by using signal analyzing and processing methods based on theory related to wavelet packet. The results show that in case of singular damage in o-ring, energy is distributed predominantly within 12.5--62.5 kHz with acoustic emission signal AERMS in double logarithmic relationship with internal leakage rate of gas volume in ball valve. Consequently, acoustic emission theory can be used to identify internal leakage of valve along gas pipeline and to determine volumetric leakage rate. （6 Figures, 10 References）