JS Water Supply Network Hydraulic Modeling And Application

The protection against water hammer and optimization scheduling of a longdistance,high-head,and gravity-flow water transmission network is of great significance in achieving balanced water distribution,maintaining the pipeline’s dynamic low pressure throughout the year,protecting pipeline safety,and ensuring normal water supply for residents.However,after the JS water transmission network was put into use,some water plants had excessive water consumption compared to the design conditions,which could cause pipeline emptying and even water hammer.Furthermore,some water plants had elevations lower than their design values,causing local high pressure and affecting pipeline safety.In actual production activities,water plants rely on manual experience to schedule operations,failing to consider the pressure balance of the entire network system,leading to varying operating conditions and underutilizing the regulating and storage functions of each water plant’s reservoir.To address these issues,this study carries out the following research work:1.Steady-state hydraulic modeling research for the JS water transmission network.Based on the CAD design drawings and SCADA measured data of the JS water transmission network,a preliminary model is established in EPANET2.2.For some nodes with significant differences between their elevation and design values,the model is first roughly calibrated,and then a steady-state verification model is established using the cuckoo search algorithm.Five stable operating conditions are used to calibrate the model parameters and complete the precise adjustment of the hydraulic model of the water transmission network,which is verified using historical operating data.By analyzing abnormal moments,it is found that the steady-state model is no longer applicable when the pipeline network system is in an unstable state.2.Water hammer analysis for the actual operating conditions of the JS water transmission network.Based on the steady-state hydraulic model,a transient hydraulic model of the JS water transmission network is established.First,the pressure sensitivity analysis of the steady-state/transient hydraulic models is conducted to determine the relationship between the node pressure and the various parameters of the pipeline network system,which is used to assist in the water hammer analysis during transient simulation.Second,valve-closing experiments are conducted at the water inlet of each water plant in the JS water transmission network to determine the safe valve-closing strategy under actual operating conditions.By analyzing the historical pressure values of pressure relief valves and the historical water consumption and pressure of each water plant,the water discharge threshold is readjusted to reduce pressure fluctuations in the pipeline network system under actual operating conditions.In addition,to address the issue of valve closing water hammer that often occurs before the first branching point(82+462)of the JS water supply pipeline network,an optimization calculation was performed based on the existing water hammer prevention facilities.New water hammer prevention devices were added to ensure the safety of the pipeline network system.3.Static/dynamic water distribution scheduling research for the JS water transmission network.First,the water consumption factor analysis is conducted to determine the outflow sequence data of the reservoir as the input parameter of the prediction model.After comparing the prediction results of several methods,the Long Short-Term Memory(LSTM)neural network model was ultimately chosen for predicting the outflow of the reservoir.A reservoir model is established based on the geometric parameters of each water plant’s reservoir,and combined with the steadystate hydraulic model of the pipeline network,a static/dynamic scheduling model of the pipeline network is established to complete the daily water distribution scheduling work.The example shows that this method can effectively reduce pipeline pressure rise and valve adjustment frequency and can be used to guide daily production activities.