Study On Calibration And Application Of Hydraulic Model Of Water Supply Network Based On Genetic Algorithm Under Underdetermined Condition

Water supply networks provides water for people’s daily life,production and fire protection.It is an important part of urban lifeline engineering.The hydraulic model of municipal water supply network can monitor the information management and operation status of municipal water supply network.It is a direct and effective technical means for municipal water supply network design planning,operation management,optimal dispatch,risk prediction and fire assessment.Because the nodal demand and pipe roughness can’t be measured directly,the hydraulic model of municipal water supply network constructed needs to be calibrated based on the measurements of nodal pressure and pipe flow.How to calibrate the hydraulic model of municipal water supply network and improve the calibration efficiency limited by insufficient measurements are the hot and difficult subjects in the research filed of water supply networks.Based on this,this paper carried out the following research es,and the relevant research results and conclusions are as follows:(1)Based on the previous research results,this paper summarized the construction and Calibration of hydraulic model of urban water supply network.Firstly,the research progress,implementation steps and theoretical research of hydraulic model construction and calibration are introduced.Then,the calibration basis and standard of hydraulic model of water supply network are summarized and analyzed.Finally,the genetic algorithm as the core algorithm of this paper is introduced in detail.(2)A water demand multiplier calibrating method based on genetic algorithm is proposed,and the average value of multiple optimization solutions is used as the fi nal solution of the water demand multiplier to solve the underdetermined optimization problem.The method takes the water demand multipliers of each node as the calibrating target and the average value of multiple optimization based on genetic algorithm as the final solution.Compared with traditional method,the average error of the node water pressure and pipeline flow after this method is reduced by 75.82% and 37.3%,its advantage is not complex grouping nodes,calibrating results can give full expression to the water difference of each node,and repeatedly check average underdetermined conditions can be greatly improved genetic algorithm to calibrate the results of stability and uniqueness,and reduce the affect of not understanding to the calibrating result,this kind of method for water supply network underdetermined check provides a feasible method.(3)The hydraulic model of the water supply network was constructed and used for calibrating research.The hydraulic model of water supply network is composed of six basic system components: nodes,pipelines,pumps,valves,reservoirs and towers.Modeling commonly used refers to the process of transforming practical engineering problems into mathematical problems according to the basic theory of hydraulics a nd establishing equations to solve them.This part compares and analyses several commonly used modeling software,and finally chooses EPANET to build the hydraulic model of water supply network in Yongsheng County,Lijiang City Lijiang.Moreover,the hydraulic model was calibrated,and the average error of water pressure at each node was less than 0.5m after calibrating,which met the calibrate requirements.At the same time,the feasibility and general practicability of the method proposed in this paper are verified.(4)The application of hydraulic model of water supply network in Yongsheng county was studied.On the one hand,the hydraulic model completed by the calibration is used to simulate the current operating conditions of the water supply network in Yongsheng County.After the simulation,the water pressure of over 90% of the water supply network nodes exceeded 0.50 MPa,and the flow rate of 62.9% of the pipe sections was lower than the economic flow rate.Through analysis and find out the problems and hidden dangers in the water supply network.On the other hand,considering that the arrangement of hydraulic pressure monitoring points and the calibration of the hydraulic model are interdependent,the data provided by a reasonable monitoring position can make the calibration of the hydraulic model more accurate,and a more accurate hydraulic model can make the monitoring point optimization more reasonable.Based on the hydraulic model,this paper uses K-means clustering method to optimize the position of the water pressure monitoring point.Compared with other clustering methods,this method can improve the calculation efficiency of high-dimensional matrices.All proposed algorithms in this paper have been programmed in Matlab platform,and the corresponding hydraulic network model is used to verify the correctness and feasibility of the proposed algorithms.