Research On Leak Detection Of The Gas Pipeline Based On Inverse Transient Analysis

With the rapid development of China's economy,the demand of gas is increasing year by year.In consideration of the natural gas' s nature,our country usually use the pipeline as the basic transportation,because most pipelines are installed under the ground,as the long-term use,the pipeline will be caused leakage accidents by corrosion,aging,third-party damage and other factors,the accidents will lead to the waste of energy resources directly,environmental pollution and huge economic losses,so detecting the gas pipelines' leakage in time and accurating the location and leakage of pipeline is essentially to ensure the gas pipeline safe.According to the basic control equation,this paper establishes a mathematical model of transient flow problem which can be used for gas pipeline leakage detection by giving specific boundary conditions.Select the characteristic line method and combine with MATLAB to solve the gas pipeline leakage transient flow model.The transient flow program of the gas-branched pipe network is different from that of the long straight pipeline where there is a cross-node.The characteristic line equation of the cross-node is simplified to a quadratic equation with four unknown quantities,and use the quasiNewton method to solve this equation.Based on the calculated parameters of the gas pipeline transient analysis and the results of sensitivity analysis,this paper establishes the anti-problem mathematical model of the leaked gas pipeline.The transient flow in the tube caused by the instantaneous closure of the pipeline's end valve is used as the excitation of the system,the pressure value of pressure monitoring point is used as a response to the system,and the leakage is the solution parameters of the system.Considering the characteristics of natural gas and the large search space of gas pipeline,in order to prevent local minimization when solve the anti-problem,this paper adopts the genetic algorithm with global optimization to make the deviation between the measured value and the calculated value minimized,and then use MATLAB programming to solve the anti-problem,through continuously iterate and correct to determine the pipeline leakage.