Research On Measurement Method Of Acoustic Wavenumber Of Water Supply Pipeline Based On Continuous Wavelet Transform

The urban water supply pipeline is the lifeline to maintain the normal operation of the city.The leakage of the water supply pipeline will cause waste of water resources,manpower and material resources,and even lead to the collapse of the ground and the collapse of houses,which seriously endangers social and public safety.Accurately determining the location of leaks in water supply pipelines is the most effective way to reduce leakage hazards.The existing pipeline leak location detection mainly relies on the time delay estimation method or the energy attenuation method,and the pipeline acoustic wave velocity or attenuation is the key parameter that affects the leak location accuracy.Based on this,this dissertation proposes a wavenumber testing and analysis method,and verifies the feasibility of the method with the help of the water supply pipeline leakage acoustic wavenumber testing test platform.The main research contents are as follows:(1)Research on wavenumber testing method based on continuous wavelet transform.According to the spectral characteristics of the leakage sound wave of the water supply pipeline,Gaussian peak fitting is used to determine its characteristic frequency band,the continuous wavelet transform method is used to decompose the leak test signal,and the waveform in the characteristic frequency band is reconstructed.The wavenumber of the reconstructed signal is calculated.(2)Construction of a water supply pipeline leakage wavenumber test platform.According to the existing test conditions,a suitable sensor,constant current adapter,assembled data acquisition box and corresponding accessories were selected to build a pipeline water leakage simulation test platform.Combined with the test requirements and equipment hardware parameters,the sampling frequency,the number of test channels and the sampling voltage range were set.By opening the fire hydrant to simulate the leakage of the water supply pipeline,the water leakage data required for the research was collected in the water leakage simulation experiment.(3)Verification of the accuracy of the measured wavenumber test of the water supply pipeline.Taking the large water leakage data collected by the water leakage test as the research object,the wavenumber is obtained according to the calculation process of the leakage acoustic wave signal wavenumber.By analyzing the spectral characteristics of the small water leakage test data,the characteristic frequency band is determined,and then continuous wavelet transform and reconstruction are performed on the data.Based on the leak location theory,the correlation of the reconstructed signal is analyzed,and the wave speed(real part value of the wavenumber)of the corresponding frequency is combined to verify the accuracy of the real part of the wavenumber through the leak location result.