Study On Attenuation Model And Check Of Residual Chlorine In Urban Pipeline Network Based On Hydraulic Model

The water supply network is an important infrastructure of cities.With the rapid development of cities and the continuous progress of human society,people’s requirements for drinking water are becoming higher and higher.At present,the number and system of urban water supply networks are very large,covering every corner of the city.At the same time,the pipeline has been upgraded at a faster speed,and pipe explosion,leakage and water pollution problems caused by pipeline aging have occurred from time to time.Therefore,in order to ensure the safe operation of the pipeline network in all aspects,it is particularly important to establish hydraulic and water quality models of the pipeline network.This article takes the water supply pipeline network in the first district of H city as the research object,and conducts a hydraulic model based residual chlorine attenuation model and verification research for the urban pipeline network.Firstly,the static and dynamic data of the water supply network in H city were analyzed using CAD and GIS data,and the pipeline roughness coefficient,node flow distribution,some typical user water supply methods,and changes in water supply curves were analyzed using on-site measurement methods.A hydraulic model was established;Simulate the hydraulic dynamic situation of the water supply network in H city,select 8 representative pressure monitoring point data and verify the simulation data,and finally obtain the difference between the hydraulic model correction value and the simulation value within the allowable range of minimum error.The residual chlorine decay first-order reaction model and Lagrange method were used to solve the residual chlorine decay problem in H city in detail.The main water reaction coefficient Kb value and the residual chlorine attenuation coefficient Kw value of the pipe wall were preliminarily determined through data such as pipeline materials and residual chlorine in the water plant,as well as measured data.Through numerical simulation of the measured residual chlorine data,the Kb value was determined to be-0.24d^-1.Based on the basic data of the pipeline and historical literature,the residual chlorine attenuation coefficients Kw1,Kw2,Kw3,and Kw4 of the pipeline wall were preliminarily determined to be-0.03m/d,-0.05m/d,-0.07m/d,and-0.09m/d,respectively.Based on the established hydraulic model of H city,data was input into the model and EPANET was used to establish a residual chlorine attenuation model for the H city pipeline network.Simulate through different time values of 24 hours,48 hours,and 72 hours.The results showed that with the increase of time,the attenuation of residual chlorine significantly increased until it tended to flatten out.In order to verify the accuracy of the residual chlorine attenuation model,15representative water quality monitoring points were selected for water quality testing.Genetic algorithm was used to automatically optimize the attenuation coefficient.After 200 iterations,the optimal coefficient was analyzed.The corresponding calibration results for Kw1,Kw2,Kw3,Kw4,and Kb were-0.04m/d,0.07m/d,0.11m/d,0.17m/d,and-0.26d^-1,respectively.The calibrated values were incorporated into the residual chlorine attenuation model,The simulated values obtained are within the allowable error range compared to the actual values,and the verification accuracy is less than 30%,meeting the accuracy requirements.At the same time,this article conducted a verification study on the residual chlorine attenuation model based on particle swarm optimization.Through orthogonal experiments,the optimal parameter combination of particle swarm optimization,pop,w,c1,c2,and m,was determined to be 60,0.6,2,and 0.3.The relevant parameters were set to the particle swarm optimization algorithm,resulting in Kb values of-0.28d^-1,Kw1 of-0.04m/d,Kw2 of-0.07m/d,Kw3 of-0.13m/d,and Kw4 of-0.16m/d.The verified values were incorporated into the residual chlorine attenuation model,The final verification accuracy of both simulated and actual values is less than 30%.Finally,a precision comparison was made between genetic algorithm and particle swarm optimization algorithm in verifying the residual chlorine decay model,and the results showed that genetic algorithm was superior to particle swarm optimization algorithm in this studyThe establishment and verification of hydraulic and water quality models have a certain reference value for real-time monitoring of the hydraulic and water quality conditions of the entire water supply network in H city,timely detection of problems in the network,and proposing solutions.It is of great significance for enhancing the safety and stability of the water supply system and improving water supply quality.