Design Of Spherical Internal Detector For Oil Pipeline And Research On The Leakage Signal Acquisition

With the rapid development of society,pipeline transportation is playing an increasingly important role in the field of transportation with its unique advantages of high efficiency,safety,energy conservation and environmental protection.But once the transportation pipeline leaks,it will cause extremely serious consequences.Survey data show that nearly 60% of the leakage accidents caused by small leakage was not found timely.Therefore,it is extremely important to carry out regular safety detection for transportation pipelines,find out small leaks in time and maintain them.Based on the above background,a detection method for the small leakage of oil pipeline is proposed in this paper,and a spherical internal detector is designed and made,which can effectively detect the small leakage of oil pipeline by collecting the sound signal at the source of the leak of the oil pipeline.The detector can not only pass through the pipeline smoothly without blocking,but also greatly improve the detection accuracy.In this paper firstly based on the working conditions of the oil leakage for pipelines,a spherical detector is designed,including its internal hardware type selection and layout,the work principle of the detector,structure and strength of the detector spherical shells,impermeability,connection mode,and the vibration mode.After that,the spherical detector prototype is manufactured.Then,a pipeline leakage model and acoustic simulation model are established,and the finite element simulation analysis of pipeline leakage near-field acoustic signal is carried out.The relationship between leakage rate and pipeline pressure and leakage aperture,the characteristics of pipeline leakage near-field acoustic signal and the relationship between leakage speed and characteristic frequency and leakage aperture and pipeline pressure are obtained.Finally,the characteristics of pipeline leakage acoustic signal are determined that the frequency range of the feature extraction is between 1.0 k Hz ? 3.1 k Hz,which provides a theoretical support for the pipeline leakage acoustic signal acquisition test and signal extraction identification.Finally,a pipeline leakage experimental section is designed and built,and the detection test of detector spherical shell seal,pipeline leakage volume detection test and leakage acoustic signal acquisition test are carried out on the experimental section with adjustable leakage aperture,so as to obtain the original acoustic signal of pipeline leakage.The original pipeline leakage acoustic signals are processed and analyzed by wavelet transform and bandpass filtering,and the pipeline leakage acoustic signals with significant characteristics are extracted and identified.The amplitude of leakage acoustic signals obtained under different pipeline pressure and different leakage aperture test conditions is compared,and a fitting function of the amplitude of leakage signals at different leakage aperture acoustic sources is obtained with the constant pipeline pressure.The experimental results are compared with the finite element simulation results,and the results show that they have a good agreement.At the same time,it shows that the spherical internal detector of pipe leakage acoustic signal designed in this study and the signal processing method adopted can detect and extract the leakage signal more accurately,and realize the more accurate location of the leakage place under certain conditions.