Study On Equivalent Estimation Method Of Micro Leakage Aperture Of Pressurized Gas Pipeline

Pressure pipeline transportation of natural gas has become the main way for urban residents to use gas.Pipeline leakage is the main factor affecting the safety of gas transportation.At present,most scholars conduct qualitative research on the leakage of pressure gas pipeline,such as acoustic excitation method and bubble method,to locate the leakage source,while the research on the leakage aperture equivalent is very scarce.The leakage aperture equivalent is the key factor to judge whether the leakage causes further harm and carry out subsequent remedial work.The research and implementation of the estimation method of leakage aperture equivalent is particularly important.This paper aims at the above problems,an experimental research platform for pressure gas pipeline leakage is built.Taking the acoustic signals generated by different leakage apertures as the research object,combined with the relevant theory of gas acoustics,the main sound sources generated by leakage are analyzed,and a simulation model for micro leakage of pressure gas pipeline is established,The velocity and sound intensity distribution of the leakage flow field of the pressure gas pipeline with the center line of the leakage hole as the center line are obtained through numerical analysis by using the finite element simulation software.Then,a multi group mean filtering method is proposed to filter the collected leakage signals.On this basis,the time-frequency domain characteristics of different leakage holes are obtained,and the relevant characteristic values are analyzed,The characteristic equation relationship between Hilbert characteristic quantity of leakage signal and aperture under three different experimental conditions is established,and the correctness of the characteristic equation for the estimation of corresponding aperture is verified through experiments and error analysis.Finally,based on the characteristic equations obtained under three experimental conditions,a real-time estimation system for the leakage aperture of pressure gas pipeline is designed on the platform of Lab VIEW,Through a large number of experiments,it is concluded that the correct rate of identifying leakage aperture equivalent under laboratory conditions is not less than 60%,which verifies the correctness and feasibility of the proposed method for estimating micro leakage aperture equivalent of pressure gas pipeline,and has certain reference significance for the field of nondestructive testing.