Research On Leakage Detection Technology Of Halogen Pipeline Based On Negative Pressure Wave Method

As a multi-disciplinary and multi-field technology,Pipeline leakage detection technology has variable detection methods.Which are mostly based on the detection of physical and chemical quantities.According to the difference between the leakage of halogen pipeline and the leakage of traditional oil,natural gas and water supply pipeline in the transmission medium and the physical properties of pipeline,this paper set single-point and large leakage problem in long straight erection halogen pipeline as the research object.The leakage detection method based on negative pressure wave was established,and the related methods were analyzed and improved.The leakage detection system of the pipeline was designed and built,and the corresponding experimental platform was set up to carry out experimental verification and analysis.The main contents of this paper are as follows:(1)The development status of pipeline leak detection technology at home and abroad was summarized.According to the degree of manual intervention,the related methods of pipeline leak detection technology were classified.The performance evaluation index of pipeline leak detection system was summarized with reference to related literatures.Different leakage detection technology of pipelines were compared and analyzed,and the idea of using negative pressure wave method was obtained.(2)The correlation analysis of transient flow in pipes was made.The basic principle of negative pressure wave method was briefly described.The propagation speed of negative pressure wave under different pipeline erection conditions was deduced and explained.By comparing and analyzing,the wavelet denoising method was obtained,which is mainly used in this paper.The relevant basic theory of wavelet denoising method was given.(3)The transient flow in the pipe during leakage was simulated on MATLAB software platform,and the change curve of pressure head along the pipeline after leakage was obtained.According to the related literature,the characteristics of the simulated negative pressure wave signal were analyzed,and the signal with corresponding characteristics is selected as the original signal in the MATLAB signal library.By comparing the denoising effect of different SNR,the combination with better effect of the threshold selection principle and the wavelet basis was obtained.Finally,the pattern recognition method was improved and simulated,and the validity of the pattern recognition method is verified by the experimental data.(4)In the denoising algorithm,an improved threshold function was used to solve the contradiction between the soft threshold function and the hard threshold function.In the calculation of negative pressure wave velocity,the calculation formula of the negative pressure wave velocity was simplified according to the small viscosity of the brine and the better fluidity in the tube.In the calculation of leakage time difference,double point reading was used to calculate the time difference and to reduce the influence of random error.The interval dichotomy and the Romberg algorithm were used to shorten the time of leakage point calculation.(5)Combined with the requirements of the project and related simulation results,based on the STM32 development board and the upper computer as the hardware foundation,MATLAB and C++ Builder as the software platform,a set of halogen leak detection system was designed and built.On the basis of building the corresponding experimental platform,through the comparison and analysis of several sets of experimental schemes,the bittern pipeline leak detection system are analyzed and evaluated from the reliability,sensitivity,accuracy and robustness.The feasibility of the system in practical application has been verified.