Simulation And Experimental Study On Leakage Of Heating Pipe Network

With the growing service life and expanding scale of heating networks in China,the failure of the pipe network frequently occurs and there are more and more leakage accidents.The leakage fault of the heating pipeline is caused by many reasons,and the time and place of the leakage are difficult to find quickly.On one hand,it affects the economic benefit of the heating department,.On the other hand,it brings inconvenience to the user’s winter heating and has a great influence on the social life.Therefore,as the energy prices and heating costs are increasing,accurate leakage diagnosis of heating network has become increasingly urgent and important.The urban heating network system is a complex and huge system,because there are many factors causing the leakage of the heating network.Therefore,the leakage detection of the pipe network is a systematic project.It is necessary to use the system engineering method and the various disciplines to carry on the comprehensive treatment.After carrying out the experiment of leakage of heating pipe network under a large number of different working conditions,the hydraulic conditions of three typical pipe network leakage are studied in detail.Based on the comprehensive analysis of hydraulic parameters such as flow rate,pressure and pressure gradient,a comprehensive detection method for leakage of heating pipe network is formedFirst of all,we use the flow judgement method to diagnose the leakage of heating network.Based on the comparison of the total flow of 18 users and the flow rate of circulating water pump in the heating experimental pipeline network,we preliminarily determine whether there is any leakage in the heating network.Then,by comparing the normal conditions of each section and the flow rate after leakage,we can get the location of the pipeline leakage.And the law of the flow change after the leakage occurs,that is,the flow value of all the users of the pipe network in the pipe section of the experimental pipe network drops,and the flow value of the users near the leakage of the pipe segment is obvious,thedecrease degree is larger,and the rest of the user’s flow decrease is less.Secondly,we use pressure judgement to diagnose the leakage of heating network.Based on the fluid network analysis method,based on the multi heat source circular heating experiment network,the hydraulic simulation model of the 18 user single heat source branch heating network is established through the MATLAB software.The maximum relative errors of the hydraulic simulation model and the experimental data are 5.67%,3.79% and 2.22%respectively under the three conditions,which verify the validity and accuracy of the simulation model.Through the comprehensive analysis of the simulation data and the experimental data of the pressure of each user under different working conditions,and the comparison of the normal working conditions and the pressure gradient after the leakage,the concrete pipe section of the leakage of the pipe network is judged.And the pressure of each user and the pressure gradient of the pipe section after the leakage occurred,that is,the water supply pressure of all the users decreased while the pipe section of the experimental pipe leakage occurred.The pressure drop of the users near the leakage of the pipe segment was larger,and the rest of the users’ pressure decreased less.And the pressure gradient of the leaking pipe section has been significantly improved,and the remaining pipe sections have no obvious change.Thirdly,based on the pressure gradient pipeline leakage detection method,the linear pressure gradient along the lines in the pipeline is linear,and the accurate location of the leakage on the pipe pipe is calculated by the method of pipeline leakage pressure gradient location.Through MATLAB software,complete the program to calculate the leakage position of the pipe network,and establish the simulation model for the leakage position of the pipe network.After calculation,the specific pipe section position of the leakage point in the pipe network is calculated.The relative errors of the three operating conditions are 0.67%,2.53%and 1.60% respectively.Finally,a simulation model of hydraulic condition is established for a real city heating network.Through the use of MATLAB software,compile and run the model simulation program,simulate the initial regulation of the pipe network,and make the pipe network achieve the design conditions.At the same time,we get the pressure values of each user node,and the curve of water supply and return pressure of the pipeline network.