Localization Algorithm Of Gas Leakage Source Based On Ultrasonic Virtual Phased Array

Large quantities of high-pressure gas pressure pipelines and pressure vessels for the storage and transportation are widely used in modern industry and life,such as cylinders,gas tanks and high-pressure gas pipelines.Due to various internal and external factors,leakage accidents often occur which not only will affect people's daily life but also cause energy waste and economic losses.Researchers of different fields has been paid more attention to pipeline gas leakage detection technology.How to locate the leak source quickly and accurately is an urgent problem to be solved.At present,the common leak detection and localization methods mainly include mass/volume balance method,negative pressure wave method,optical method,cable sensor method and acoustic emission(AE)method.Compared with other methods,the AE method has the advantages of high localization accuracy,short detection time,low false alarm rate and strong adaptability.Therefore,the detection and localization of the leakage source by AE method has become a hot spot in the field of leak detection and localization.The AE method can be mainly divided into two parts: time domain detection method and spatial domain localization method.The spatial domain method has higher detection precision and sensitivity than the time domain method,so this method is most commonly used in industrial applications.However,the traditional spatial domain method usually uses L-shaped arrays and U-shaped arrays with small number of array elements,accompanied by the use of multiple signal amplifiers and multiple data synchronous acquisition systems,resulting in a complicated system structure and high cost.At the same time,the accuracy of the leak localization is also limited by the number of array elements.Aiming at the problems of the above methods,this paper proposes a gas leak location method based on virtual phased array consisting of only two sensors.This method uses a single sensor to continuously scan to obtain the amplitude information of the leakage signal,and introduces a reference sensor to obtain the phase information.In this study,two sensors can be used to construct a larger number of arrays.The results show that this method can obtain high-precision gas leak localization results,significantly reduce the complexity of the leak detection system,and also effectively reduce the system cost.This study proposes a virtual beamforming algorithm based on traditional array signal processing,which combines the traditional array signal processing algorithm with the virtual array to effectively estimate the direction of gas leakage.At the same time,the cross-power spectrum algorithm is used to solve the problem that the signal acquisition is not synchronized.And the algorithm is used to replace the signal synchronous acquisition circuit.In this study,the effects of simulation experiments with different array elements and different array distance on the accuracy of the virtual beamforming algorithm are discussed.The experimental results show that the angular resolution of the localization results increases with the increase of the scanning array elements;the distance of the array elements is much lower than the half wavelength and the number of array elements of the virtual array is fixed.As the scanning pitch increases,the aperture of the array becomes larger,thereby the resolution of the localization is improved.Then the effectiveness of the proposed gas leak localization method was verified by several actual gas leak detection experiments,and the error analysis was carried out.The results show that the method can locate the gas leakage source with high precision within the effective detection distance.This method can locate the leakage source with low cost,high efficiency and high precision.It has broad application prospects.