Study on leakage identification and localization in water pipelines based on nozzle-excited pressure waves

Abstract

[Objective] Pressure waves have been widely applied in the field of pipeline leakage detection due to their ability to carry energy and information. The aims are to address the limitations of existing pressure wave generators and to further investigate the excitation and propagation characteristics of pressure waves in leaking water pipelines. [Methods] A nozzle-type pressure wave generator was designed, which actively excited pressure waves by using compressed gas to impact the water pipeline through a nozzle, and was applied to an experimental platform for water pipeline leakage detection. In a pipeline about 120 meters long, the effects of intake pressure, intake time, leakage aperture, and leakage location on the upstream and downstream pressure wave characteristics of the leakage hole were tested under both leakage and non-leakage conditions. Leakage localization was performed using two methods: the difference method based on the pressure curve difference between leakage and non-leakage conditions, and the slope method based on the slope of the pressure curve under leakage conditions. [Results] Experimental results showed that the presence of pipeline leakage led to distortion of the pressure waveform and the occurrence of waveform separation at the upstream monitoring point of the leakage hole, and also caused overall pressure attenuation at the downstream monitoring point. As the intake pressure increased, intake time extended, and leakage aperture enlarged, these leakage characteristics became more pronounced. The distortion position of the pressure waveform at the upstream monitoring point varied with the leakage location. The distortion time point could be effectively identified, and the leakage could be localized using the difference method and the slope method. The maximum absolute localization errors using the difference method and the slope method were-2.31 m and-2.78 m, respectively, with maximum relative errors of-5.64% and-8.24%, respectively. [Conclusion] The research findings verify the feasibility of using a nozzle-type pressure wave generator for water pipeline leakage detection and can provide references for leakage identification and localization technologies in water pipelines.

Keywords

pressure wave / pressure wave generator / nozzle / water pipeline / leakage characteristics / leak localization / difference method / slope method