Reaserch On Water Distribution Network Transient Flow Model And Its Application Demonstration

With the increase of water usage and aging water pipes,water supply network exposes serious water loss problems,and the most obvious is the frequent problem of burst pipes.Under the background of the "Digital City" and the water supply information construction,many companies have accumulated a large number of water supply network based data,which need a reasonable hydraulic model for analysis and water hammer simulation.The water hammer model has been applicated widely abroad,there are a large number of mature commercial software.The research in China started late.The current study appear in simple topological structure of long distance water conveyance system more,but the municipal complex of water hammer model less.Municipal pipe network geographic information system(GIS)information and the daily management information are used to establish the microscopic hydraulic network model.The supervisory control and data acquisition(SCADA)monitoring system’s data and artificial manometry data are used to check the accuraty of pipe network model,thus a useful hydraulic model can be built.Several methods are used to simplify the hydraulic model: branch collapsing,parallel pipe merging,inline isolation valve replacement.The transient analysis model is built after simplification.In this paper,the experiments under different conditions of water hammer phenomenon are designed to conduct the qualitative research of complex pipe network.The 100 Hz pressure sensor is used to collect pressure data that can be transferred to a computer by ZigBee wireless transmission.Several cases listed for complex pipeline system are studied: steady state,pump shut off,pump start,pump restart up after shut off,valve open,valve close,valve open after close,flow regulate.The pressure changes of two point are studied under these conditions to study the rule of water hammer in complex pipeline system.The data analysis can provide reasonable proposals for pipeline management,and the pipe brust accidents can be classified by cluster analysis.Two main roads are chosen as the objects of study with the water hammer model.Seven scenarios listed for complex pipeline system are studied: the 3# pump shut off,the 4# pump shut off,3# and 4# pump shut off,factory valve closing time in 30 s,60s,90 s,120s.The high pressure and low pressure can be found through the simulation of different scenarios.The pump shut offscenarios are affected by topology.The valve close time after 90 s can meet safety requirements.According to the result of many scenarios,the analytic hierarchy process(AHP)method can be used to conduct the risk assessment of pipelines combining hydraulic factors and non hydraulic factors of water hammer pipe burst.Finally,two practical cases are studied,the protective measures of water hammer are proposed.Programs to valve replacement project and the phenomenon of the hydraulic are analysed before and after valve close.This paper describes the hydraulic model and water hammer model.The network is designed to study water hammer characteristics of complex pipe network.The analysis and assessment can be conducted using the model of the pipe network water hammer,and the model can be usd in the actual project.The exploration of municipal pipe network water hammer model can provide a powerful tool for the future water supply network security management.