A single-sensor modal acoustic emission time-frequency location method for fluid pipeline leakage

Abstract

The invention discloses a modal acoustic emission time-frequency locating method adopting a single sensor for a fluid pipeline. The method comprises the steps of 1, picking up acoustic emission signals of pipeline leakage through the single acoustic emission sensor at any contactable terminal of the leaking pipeline; 2, carrying out time-frequency analysis on the acoustic emission signals of leakage for obtaining a time-frequency spectrum; 3, extracting time information and frequency information corresponding to three peaks of the time-frequency spectrum of the leakage signals; 4, obtaining the time differences between any two modal signals according to the three kinds of peak time, substituting three kinds of peak frequency into corresponding frequency dispersion curves of three modes and obtaining the sound speeds of the signals of the three modes; 5, obtaining the positions of three leakage points according to the obtained three time differences and sound speeds and averaging the leakage points. According to the method, just one acoustic emission sensor is needed for determining the position of the leakage point, the operation is easy and convenient, and the method can be conveniently applied to engineering; pipeline leakage can be accurately located on the condition that leakage cannot be located because of multiplex modes and the frequency dispersion characteristic.

Description

technical field [0001] The invention belongs to the field of pipeline leakage detection, and in particular relates to a time-frequency positioning method for single sensor modal acoustic emission of fluid pipeline leakage. Background technique [0002] As an efficient and convenient fluid transportation method, pipeline has been widely used in the transportation of natural gas, oil and other fluids. Due to natural or man-made reasons: pipeline aging, corrosion, geological subsidence, irregular construction, etc., pipeline leakage occurs from time to time. Leakage of gas pipelines causes resource waste, environmental pollution, and even explosions, poisoning and other vicious accidents, which pose a serious threat to people's lives and properties. Therefore, the detection and location technology of fluid pipeline leakage is very necessary to reduce the harm caused by pipeline leakage. [0003] Acoustic emission technology, as a real-time in-service non-destructive testing m...

AI Technical Summary

Problems solved by technology

This method overcomes the problem of large positioning errors caused by the dispersion of leaked acoustic emission signals. It essentially uses a time-frequency positioning method based on the cross-correlation function of a single dominant mode signal, but the actual leaked acoustic emission signal is multiple Modal signals (bending mode, torsional mode, longitudinal mode and fluid-dominant mode), which will lead to weak correlation of the leakage signals collected at both ends of the leak when performing cross-correlation analysis, resulting in large cross-time-frequency positioning errors

In addition, this method still requires two sensors to locate the leak point, which will cause a certain degree of inconvenience in engineering applications

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