Study on acoustic vibration of pipeline leakage and its propagation characteristics

Pipeline leakage detection is an important link to ensure the safe operation of production. To study the vibration changes in the pipe wall caused by leaks and the propagation characteristics of leakage sound waves within the pipe wall and the medium inside the pipe, a physical model of pipe leakage was established. The effects of sound source frequency, leakage aperture, and pipe size on sound wave propagation were analyzed using an acoustic-solid coupling method. The results show that: the vibration of the pipe wall exhibits regular periodic changes in both the axial and circumferential directions. The leaking sound wave reflects and superimposes within the pipe, creating a standing wave phenomenon. The vibration displacement of the pipe wall and the sound pressure inside the pipe increase with higher sound source frequencies and larger leakage apertures but decrease as the pipe size increases. Combining Timoshenko beam theory, longitudinal and transverse waves do not exhibit dispersion in the frequency range of 0-5000Hz, and the wave speed of surface waves increases with increasing frequency. Experimental studies on the leakage device indicate that the vibration signal during the initial leakage stage is characterized by sudden changes, and four characteristic frequencies are present within the 5000Hz range, with little change in the distribution of frequency components. Pipe vibration signals are influenced by the leakage aperture and internal pipe pressure; as the leakage aperture and internal pipe pressure increase, the intensity of the pipe wall vibration signal also increases.