输气管道声波法泄漏检测技术的理论与实验研究

为探究输气管道声波法泄漏检测技术的基本原理和研究方法,建立了输气管道泄漏仿真模型和实验模型。首先,研究输气管道发生泄漏时声波产生机理,从而明确声波法泄漏检测技术的工作原理;其次根据声波法泄漏检测的原理建立Fluent仿真模型,通过CFD软件模拟输气管道泄漏得到流场和声场,得到声波信号特征;再次根据声波法泄漏检测的原理搭建实验管道,设计完成声波信号数据采集终端,并在仿真结果指导下完成输气管道泄漏检测实验,采集得到实验数据并进行分析,得到泄漏时声波信号特征并对仿真结果进行验证;最后对比多工况条件下的实验结果和仿真结果,分析不同工况条件对压力波动值的影响规律,从而总结输气管道声波法泄漏检测的仿真与实验研究方法,为声波法泄漏检测的实际工程应用提供理论基础。研究结果表明:输气管道泄漏产生的声波来源于泄漏时气体不稳定流动产生的偶极子声源和四极子声源;仿真模拟和实验研究的方法都可以完成声波法泄漏检测技术的研究,可以对声波法泄漏检测技术的推广和工程应用提供强大的理论支持和可行性保证。结论是:声波法泄漏检测技术可以很好的检测输气管道泄漏,是一种灵敏度高,检测时间短,值得推广的方法。

Theoretical study and experimental study on leak detection for natural gas pipelines based on acoustic method

In order to study the fundamentals and research methods of leak detection for natural gas pipelines based on acoustic method,the simulation model and experiment model are established.First the aero-acoustics generation mechanism is researched when leak occurs to find out the fundamentals of leak detection for gas pipelines based on acoustic method.And then the simulation model is established on CFD software by which the flow field and the sound field are aquired to analyze acoustic signal characteristics.Thirdly,based on acoustic leak detection method, a complete set of high-pressure gas pipeline leak experimental device and acoustic data acquisition system is designed and the experiment is accomplished based on the consequences of simulation.The paper analyzes the data acquired by experiment and concludes the acoustic signal characteristics which are used to correct the characteristics concluded by simulation method.Finally the paper compares the experimental method with simulation method under variable conditions and find out the law between the different conditions and pressure perturbations which provides a theoretical basis for the engineering applications of leak detection for gas pipelines based on acoustic method.The results indicate:it is the quadrupoles and the dipoles generated by turbulent fluctuations that causes the leak-acoustics;both the simulation method and the experimental method can be applied to study acoustic leak detection method. Conclusions can be drawn that acoustic leak detection method has many advantages such as high sensitivity and less detection time so it can be used in natural gas pipelines better.