Leakage Detection And Location Method Of Non-uniform Slurry Pipeline Based On Virtual Acoustic Wave

With the increasing demand for mineral resources in China,the traditional way of transporting ore by road and railway has been gradually replaced by the way of pipeline transportation.In order to ensure the safety of pipeline transportation,it is necessary for us to study the leakage detection technology of pipeline.In this paper,the virtual acoustic wave method combined with wavelet filtering technology is used to detect and locate the leakage of slurry pipeline.The filtered pressure signal is converted into a virtual acoustic signal,and the abnormal signal is detected.The leakage location is carried out according to the characteristics of the non-uniform slurry conveying pipeline.The leakage detection ability of the virtual acoustic wave method is analyzed from the Angle of frequency domain and time domain.And the reason why the abnormal signals of abrupt and slow variation can be detected simultaneously by adjusting the model parameters(discrete frequency)is explained.On this basis,the abnormal signal detection method based on the frequency sweep method is proposed,which can effectively improve the detection rate of different abnormal signals.The time difference error of upstream and downstream signals with different values of discretization frequency is analyzed,and the selection basis of discretization frequency is given from the perspective of positioning accuracy.According to the characteristics of the virtual acoustic wave method,a wavelet decomposition scale optimization method based on maximization of signal-to-noise ratio(SNR)is proposed.By analyzing the limitations of this method,it is found that the leakage detection idea of "first wavelet decomposition scale optimization followed by abnormal signal extraction"does not fit the virtual acoustic wave method.Based on the actual simulated leakage signal,the selection of wavelet decomposition scale is given from the perspective of location accuracy.An optimization method of wavelet decomposition scale based on the detection of abnormal signals is proposed,which combines wavelet filter and sweep method.According to the characteristics of drastic change of sound velocity in non-uniform slurry conveying pipeline,a leak location method based on piecewise sound velocity correction was proposed.The distribution relationship between the sound velocity and the concentration in the slurry along the passage and the corresponding location formula were derived,which reduced the error of leakage location under the condition of non-uniform slurry concentration.Using the actual pressure data for run offline for a long time to test the proposed approach.The results show that the method proposed can accurately detect the leakage signal,accurate positioning and low rate of false positives.The method proposed in this paper has good practical value.