天然气管道泄漏声源特性及传播机理数值模拟

管道泄漏声源特性和传播机理决定了音波法在管道上的可检测性，管道泄漏引发的音波能量大小和其沿管道传播的衰减程度分别与泄漏口径大小、管道内压和管道长度等因素有关。以天然气管道泄漏时的气动噪声为研究对象，采用适用于高马赫数流场的MÖhring声类比对其进行模拟计算，建立了不同压力、不同泄漏孔径条件下的天然气管道泄漏噪声仿真模型，得到了天然气管道泄漏声源的相关特性，利用试验数据验证了计算模型的准确性。以该声源模型为基础，建立了音波在管道内的二维传播模型，通过模拟结果与现场试验的比较分析，表明天然气管道泄漏音波的超低频段（低于5 Hz）可在管道内传播较远距离并能被声波传感器所探测，从理论上验证了音波法在天然气管道泄漏检测领域的良好应用前景。

Simulation research on leak source characteristics and propagation mechanism for natural gas pipeline

The detectability of acoustic methods for pipeline leakage is jointly determined by the characteristics of acoustic sources and the propagation mechanism of acoustic signals. The acoustic energy caused by pipeline leakage and the attenuation of its propagation along the pipeline are respectively related to the size of leakage hole and the operation pressure and length of pipeline. The aero-acoustic noise generated by pipeline leakage is simulated by using Mhring acoustic analogy, and an aero-acoustic simulation model for gas pipeline leakage associated with different pressures and leak-hole sizes are established. The characteristics of acoustic source in pipeline leakage are obtained, and the accuracy of the proposed simulation models is validated with experimental data collected with the pipeline leakage simulation platform. The aero-acoustic simulation model is then used to establish a two-dimensional propagation model for acoustic waves in pipeline, and the simulated data are compared with field data for validation. The results show that acoustic waves of ultralow frequency (<5 Hz) can propagate in pipeline for a long distance and are capturable by acoustic sensor. The acoustic methods have a great application prospect in gas pipeline leak detection theoretically.