Research On Key Technologies Of Acoustic Sensor For Pipeline Leakage Detection

With the rapid development of the natural gas pipeline industry and the increase in the service life of pipelines,pipeline leakage accidents occur frequently,and it is necessary and important to strengthen the real-time leak detection of pipelines.In recent years,there have been numerous methods to detect leaks in pipelines using various types of sensors,among which the acoustic wave method leak detection technology based on acoustic sensors has strong adaptability,short detection time,high sensitivity and accuracy,and has great application prospects in the field of pipeline leak detection.In this paper,we propose a sensitive point analysis method for acoustic signals of gas transmission pipeline leaks and design a new type of inserted acoustic sensor,the main work done is as follows:(1)From two perspectives of gas jet and gas pipeline leakage diffusion model,the fluid motion control equations and turbulence numerical simulation methods are studied,and the characteristics of flow field and acoustic field when gas pipeline leakage occurs are theoretically studied by combining fluid mechanics and pneumatic acoustics theories,and the characteristics of the sound source when the pipeline leakage is analyzed,and the sound source composition of the leakage acoustic signal is determined.(2)According to the actual working conditions of this study,the matching calculation model and method are selected to study the multi-physical field coupling model of gas pipeline leakage with complex structures such as branch pipe,ball valve and leakage hole.Firstly,the flow field and pressure field during leakage were simulated and analyzed,and then coupled with the sound field to obtain the simulated leakage acoustic signal.In addition,the characteristics of the simulated leakage acoustic signal such as pressure fluctuation,spectrum,power spectral density and sound pressure level were analyzed in the time domain and frequency domain under different working conditions.(3)According to the characteristics of the leakage acoustic signal itself,the effective leakage frequency component amplitude and power spectral density were taken as the evaluation criteria,aiming at the monitoring points located at different positions in the multiphysical field coupling model,the sensitivity of the main pipe and the branch pipe to the leakage acoustic signal was studied,and a method for analyzing the sensitive points of the leakage acoustic signal in the gas pipeline was proposed.(4)A new type of inserted acoustic sensor is designed.The inserted acoustic sensor and the traditional acoustic sensor are respectively used to collect the experimental leakage acoustic signals in the gas pipeline leakage detection experimental system under different operating pressure and different leakage aperture conditions,and the signal-to-noise ratio is used as the evaluation index to verify the performance of the inserted acoustic sensor.