Leak detection is one of the most important issues in natural gas pipelines operation, major accidents can result from pipe gas leaks in pipelines that transport high-pressure gases. Natural gas pipeline leakage can cause huge economic losses and affect public health. Currently, pipeline leak detection relies on the semi-empirical formula based on the traditional basis. However, such methods have obvious limitations. It is impossible to predict the new process in a forward-looking way, which leads to a sharp increase in cost. The infrasonic wave method offers the possibility of continuous acoustic monitoring of pipelines and remote detection of leaks. In this work, the time-frequency signal of pipe leakage acoustic wave was studied by using the method of “acoustic - pipe and acoustic - pressure” multi-physical field coupling. Finally, the acoustic leakage monitoring method was applied to the field pipeline. The results show that: 1) natural gas pipeline leakage is a kind of broadband noise. With the increase of frequency, the energy tends to oscillate and decay; 2) the acoustic wave propagates from the leakage hole, and the amplitude decreases rapidly. 3) the leakage acoustic energy is mainly concentrated below 20 Hz, and the mean sound pressure increases with the increase of internal pressure and leakage diameter; 4) ultra-low frequency sound pressure level (SPL) is of great significance to the detection of natural gas pipeline leakage by the acoustic method. The field experiment demonstrates that this method can improve the detection ability of small leakage. Hence, the proposed method provides a new approach for the detection of pipeline leakage in technology popularization and engineering applications.

泄漏检测是天然气管道运行中最重要的问题之一，输送高压气体的管道发生管道气体泄漏会导致重大事故。天然气管道泄漏会造成巨大的经济损失，影响公众健康。目前，管道泄漏检测依赖于传统基础上的半经验公式。但是，这样的方法有明显的局限性。无法前瞻性地预测新工艺，导致成本急剧增加。次声波方法提供了对管道进行连续声学监测和远程检测泄漏的可能性。本文采用“声-管-声-压”多物理场耦合方法研究管道泄漏声波时频信号。最后，将声泄漏监测方法应用于现场管道。结果表明：1）天然气管道泄漏是一种宽带噪声。随着频率的增加，能量趋于振荡和衰减；2）声波从泄漏孔传播，幅度迅速减小。3）泄漏声能主要集中在20Hz以下，平均声压随着内压和泄漏直径的增大而增大；4）超低频声压级（SPL）对声学方法检测天然气管道泄漏具有重要意义。现场实验表明，该方法可以提高小泄漏的检测能力。因此，