Study on the transient structure and acoustic emission characteristics of gas pipeline leakage holes at leakage instant

Pipeline plays an important role in the process of natural gas transportation, and pipeline leakage is related to energy, environmental protection, and security issues. The transient structure and sound source signal characteristics are the key to the accurate detection and location of leakage holes in gas pipelines. A fluid-structure coupling model of gas pipeline leakage is established in this paper. The effects of different pipe pressure and leakage apertures on transient structural parameters such as flow rate, stress, and displacement of leakage hole are studied. The change of acoustic emission signal at the moment of leakage is analyzed by fast Fourier transformation. The results indicate that the distribution of the flow line near the leak hole becomes more and more disordered with the increase in the leak aperture. The rate of leakage hole increases with the increase in pressure. The stress near the leak hole is distributed in a cross shape, and the stress near the leak hole increases with increasing pressure and decreasing aperture. The total displacement around the leakage hole is an "8"-shaped distribution, which increases with the increase in pressure and aperture, and the maximum displacement is located on the side of the pipeline. The frequency of the maximum stress value near the leakage hole is 1 kHz. The radial displacement amplitude is the largest, and its main frequency is 1-5 kHz. This study provides a theoretical basis for the accurate identification of pipeline leakage instantaneous signals.