输气管道泄漏声波衰减模型的理论研究

A theoretical study on the attenuation model of leakage acoustic waves for natural gas pipelines

一直以来,在国内外声波传播特性的研究中,幅值衰减模型的建立没有考虑管道内气体流动的影响,使得声波传播规律的研究并不充分。基于此,确定了泄漏声波在输气管道中的传播以一维平面波形式进行,推导了泄漏声波的传播公式,建立了耦合黏热效应、湍流效应和气体流动的泄漏声波幅值衰减的理论模型,从理论上建立了黏性均匀流动介质中考虑气体流动、湍流效应和黏热效应的声波幅值衰减模型;然后通过实验拟合得到了10 mm管线顺流和逆流情况下的衰减因子,理论计算值与实验拟合值相比,采用原始信号计算得到的顺流衰减因子误差都在6. 0%以内,采用小波特征计算得到的衰减因子顺流时误差都在7. 0%以内,逆流时误差也都在12. 0%以内,并分析了误差来源。研究结果表明:所建立的声波幅值衰减模型充分考虑了黏热效应、湍流效应和气体流动作用,试验验证了该模型的准确性。

Studies on the propagation model for natural gas pipelines have not been considered thoroughly.When the propagation characteristics are studied,the influences of gas flow on the attenuation model were not consideration.Therefore,the propagation equation was deduced in the gas pipelines.The amplitude attenuation models were established in theory and in experiments.Firstly,the theoretical attenuation model was established in the viscous flow with uniform velocity considering gas flow,turbulent effect and viscothermal effect.Then the attenuation factors were calculated in experiments and in theory in 10 mm gas pipelines.When the original signals were processed,the upstream errors calculated in theory were less than 6.0%.When the wavelet transform(WT)signals were processed,the upstream errors calculated in theory were less than 7.0%while the downstream ones were less than 12.0%.And the reasons for the errors were analyzed.The results show that the established attenuation model can be verified by the experiments.