Pipeline Leakage Detection And Localization Based On Acoustic Emission Signal

With the vigorous development of the pipeline transportation industry,problems such as pipeline aging and pipeline leakage have become increasingly prominent.Pipeline leakage will not only cause environmental pollution,but also seriously affect people's lives and property safety.Therefore,the research on pipeline leakage detection and leakage point location is of great significance.This paper analyzes the key and difficult problems in the pipeline leakage and location research,and designs a pipeline leakage acoustic emission signal detection and location system based on STM32.The main work of this article is as follows:(1)Through the analysis of the existing pipeline leakage detection methods,and based on the generation principle and propagation characteristics of the pipeline leakage acoustic emission signal,it is proposed to complete the pipeline leakage location by detecting the pipeline leakage acoustic emission signal.(2)Through the analysis of existing signal denoising methods,an improved wavelet threshold function is designed.The improved wavelet threshold function is used to denoise the noisy signal.The results show that the improved wavelet threshold function has better denoising effect than other threshold functions.Based on the above analysis,through the advantages of the variational modal decomposition VMD algorithm in signal processing,a joint denoising algorithm of the variational modal decomposition VMD and an improved wavelet threshold is proposed.Through the denoising processing of different noisy signals with known signal-to-noise ratio,it is verified that the proposed joint denoising algorithm can improve the signal-to-noise ratio more effectively.(3)Completed the design of a pipeline leak detection and location system based on STM32.The hardware mainly includes the selection of the single-chip microcomputer and the sensor and the design of the signal conditioning module;the software mainly includes the design of the lower computer and the upper computer,the lower computer mainly completes the software denoising processing of the collected sensor signals,and at the same time determines whether the pipeline is leaking,and estimate the location of the leakage point,then transmit the obtained pipeline leakage information to the host computer for display.(4)A pipeline leak detection and location system was built,and related experiments were carried out.In the experiment,three kinds of generalized cross-correlation algorithms weighted by different weighting functions were used to estimate the time delay of the signals of the two sensors and the results were compared.Finally,the generalized cross-correlation algorithm weighted by the SCOT function was used to realize the leakage acoustic emission signal of the pipeline,at the same time completed the estimation of the pipeline leakage location.Experimental results show that the pipeline leak detection and location system designed in this paper can effectively detect whether the pipeline is leaking,and can accurately estimate the location of the leak.At the same time,the experimental results prove that the joint denoising algorithm designed in this paper can effectively suppress the influence of noise on the positioning accuracy.