Research On Checking Hydraulic And Water Quality Model For Water Distribution Networks

The subject mainly discusses the hydraulic and quality model of water distributionnetworks, with checking the model. The accurate hydraulic and water quality modelsof water distribution networks can reflect the hydraulic and water quality of thenetworks on line, and we realize the water quality state of the whole waterdistribution networks. This is the base of scheduling the water distribution networks.At the same time, it is the working platform for the follow-up study, such as pollutionsources tracking in the water distribution networks.Using Supervisory Control and Data Acquisition System (SCADA) andGeographic Information System (GIS) collect and settle the data of the waterdistribution network, and combining with the investigation and artificial detectiondata set up the topology structure of water distribution networks. we build thenetworks’ hydraulic model. First the hydraulic model is checked by artificial means,and then analyzed the parameters of the model with genetic algorithm automatically.There are discussed the A. Hazen and G. S. Williams coefficients of pipes and somenodes’ flow with genetic algorithm to improve the accuracy of hydraulic model. Bydiscussing the model of the G city’s water distribution networks, it finds that onlyadjusting the A. Hazen and G. S. Williams coefficients of pipes can meet the requiredaccuracy of the network’s hydraulic model. In addition, adding some nodes’ flow tocheck, it can’t improve the accuracy of hydraulic model better. The accuracy of thehydraulic model about part of G city’s water distribution network is as follows: therunning status of the hydraulic model is as the same of actual water distributionnetwork. The average of absolute error about the pressure data in monitoring stationsis0.305m. The proportion of the errors being less than0.5m is85.52percents in thetotal. This meets the hydraulic model accuracy standard.Based on the hydraulic model, and using EPANET software calculates age of thenetwork. Through the analysis of the age calculation result, it can be seen that the ageof most nodes is less than20h, and most of the water in the water distribution networkwill be replaced within24h. The average age of all nodes in the network is about15h,and the maximum age of all nodes is46h. Although the water needing to flow throughother water distribution network before flowing into the network, the stopping time ofthe water in the other water distribution network is less than24h. So the age of thewhole network meets the requirement of age in water distribution network. It makes sure of the chlorine residual decay coefficient about the part of G city’swater distribution network, with discussing the experimental data and the Existingconclusion about the chlorine residual decay coefficients. So we are based on theresearch to build the chlorine residual model of the network. We build the model bytwo methods. One is making sure the chlorine residual decay coefficients byexperimental data, the other is by the mathematical model of the chlorine residualdecay coefficients. It checks the accuracy of the models by genetic algorithm, andfinds that two models built by the two ways have the similar results. But the latter isbetter in adaptability and management. The water quality of the whole network meetsthe requirement of the 《Standards for Drinking Water Quality》(GB5749-2006). Thechlorine residual in the network is necessary to hold the quality of the water statically.