Research On Leakage Location Of Tailings Conveying Pipeline Based On Infrasonic Signal

Pipeline transportation has gradually become the preferred transportation method in China’s modern industry due to its advantages of economic convenience,safety and reliability.However,with the increase in the service life of the pipeline,it is inevitable that the pipeline will break and cause leakage.The leakage accident will not only cause the shutdown of the pipeline,but also cause pollution to the surrounding environment.In order to improve the safety level of pipeline transportation,the positioning problem in leakage detection of tailings transportation pipelines based on infrasonic signals has been studied in this paper.The main research work is as follows:(1)This paper introduces the generation mechanism of leakage signals in tailings conveying pipelines,analyzes on the basic characteristics of leakage signals,the propagation speed of infrasonic waves,and the main sources of noise.Based on the principle of pipeline leakage location,the pipeline leakage location formula is derived.(2)The wavelet threshold denoising algorithm is used to denoise the leakage signal,and the db4 wavelet basis function is selected to decompose the leakage signal into six layers.Based on fixed thresholds and soft and hard threshold functions,improved thresholds and threshold functions are proposed.The results show that the improved threshold function achieves a maximum signal to noise ratio of 51.6721 for the first station signal,a minimum root mean square error of 0.1067,and a maximum signal to noise ratio of 51.2986 for the tail station signal,The minimum root mean square error is 0.1391,indicating that the improved denoising method has better denoising effect compared to traditional denoising methods,making the denoised signal closer to the real leakage signal.(3)The cross correlation time delay estimation method is used to locate the leaking signal.Based on the generalized cross correlation time delay estimation algorithm,a quadratic cross correlation time delay estimation algorithm is proposed.The results show that the maximum error of the time delay estimation obtained by the quadratic cross correlation time delay estimation method is 9.38%,and the minimum error is 6.53%,both of which are kept within the range of 10%,It is shown that the quadratic cross correlation time delay estimation algorithm has better anti noise performance compared to the generalized cross correlation time delay estimation calculation method,and to a certain extent improves the accuracy of the time difference between the leakage signals received at both ends of the pipeline.(4)The overall structure of leakage location for tailings conveying pipelines was designed,combining the hardware module of the control room with the software module of the central station.The propagation speed of infrasonic waves was determined through multiple liquid discharge operations,and experimental tests were conducted to simulate a real pipeline leakage environment.The experimental results showed that for a 2km tailings conveying pipeline,the positioning error of leakage points at both 20 mm and 25 mm leakage apertures was within ±50m,The relative positioning error is maintained within 2.5%,effectively meeting the technical requirements of the engineering project,and verifying the feasibility of the leakage positioning method in this article.