Leakage signal propagation speed measurement method based on short-time energy and linear fitting

Abstract

The invention relates to a leakage signal propagation speed measurement method based on short-time energy and linear fitting. Two ways of knocking signals are respectively preprocessed; the preprocessed signals are squared; mobile windows are added to respectively calculate the short-time energy of the two ways of knocking signals; thresholds are selected according to short-time energy curves to determine starting points of the two ways of knocking signals and to calculate the propagation time of the knocking signals; the average propagation time of the knocking signals under the same one propagation distance is measured; the average propagation times under different propagation distances are linearly fitted to obtain a fitted straight line; and the reciprocal of the slope of the fitted straight line is the sound velocity.

Description

technical field [0001] The invention belongs to the technical field of leakage detection and positioning of fluid conveying pipelines, and in particular relates to a measurement method of leakage signal propagation velocity (hereinafter referred to as sound velocity) based on short-term energy and linear fitting based on a data acquisition system. Background technique [0002] In the maintenance of fluid transmission pipelines, pipeline leakage detection and location technology is very important. Existing methods for detecting and locating pipeline leaks include cross-correlation detection methods based on the principle of acoustic emission, and pipeline model methods, flow balance methods, pressure gradient methods, gas tracking methods, and infrared imaging methods based on non-acoustic emission principles. Among them, the cross-correlation detection method based on the principle of acoustic emission has been widely used because of its low detection cost and high detection...

AI Technical Summary

Problems solved by technology

[0009] The problem with this method is that the number of piezoelectric sensors used is large, and three piezoelectric sensors are required at the front and back of the valve, and a total of six piezoelectric sensors are required; and the installation position of the sensor is limited by the position of the valve.

[0011] The problem with this method is: this method is not practical

[0014] When the percussion signal propagates on the pipe wall, the waveform of the signal will be distorted and the energy will be attenuated, and the percussion signal is easily interfered by external environmental noise and echo during the propagation process, causing the two piezoelectric sensors to pick up The waveform similarity of the knocking signal obtained is poor, and the cross-correlation algorithm requires that the waveforms of the two signals are similar. Therefore, using the cross-correlation algorithm to calculate the propagation time of the knocking signal will bring a large error, which will affect the measurement of the sound velocity.

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