Monitoring Pipeline Leaks Using Fractal Analysis of Acoustic Signals

This paper proposes a method for searching for pipeline leaks by analyzing the Hurst exponent of acoustic signals. The investigations conducted on the laboratory setup and the current pipelines of the water supply system. During the experiments, through defects of the round shape-type pipeline with diameters from 1 to 5 mm were modeled. For calculating Hurst exponent, rescaled range analysis (R/S analysis), and detrended fluctuation analysis (DFA) were used. The research results have shown that pipeline leaks are reliably detected by analyzing the Hurst exponent of acoustic signals. The signals of a defect-free pipeline are close to the level of a deterministic signal. When a leak occurs in a pipeline, the Hurst exponent decreases. Pipeline fluctuations are anti-persistent nature. It is shown that a change in the size of the through hole in the pipeline wall does not have a significant effect on the value of the Hurst exponent of acoustic signals. These results are explained by using spectral analysis and CFD modeling (Computational Fluid Dynamics modeling) methods in the Ansys Fluent software (v. 19.2). It has been established that the spectral components that contribute most to the fractal structure of signals are concentrated within the frequency range from 0 to 2 kHz.