Study On Zoning Of Pressure Variation In Municipal Water Supply Network And Criterion Of Superimposed Water Supply

Superimposed pressure water supply contains great potential for energy saving,carbon reduction and water quality assurance,but because of its disorderly use will have an impact on municipal water pressure,and the lack of practical and detailed access provisions in various cities,the access conditions for superimposed pressure water supply have become increasingly stringent in recent years,and even stopped the approval.In order to make full use of the potential of energy saving and water quality assurance,the admission criteria of secondary water supply equipment are studied.Based on the hydraulic model,the pressure variation zoning of municipal water supply network is proposed.Firstly,the simple model of the water supply network in the main urban area of C city,a western province,is established by using PDA model,GIS and SCADA system,EPANET2.2.PF algorithm based on En KF method is used to check the node flow.MCMC method,M-H sampling and DREAM algorithm are used to check the model parameters,and the MCMC-PF joint checking method is established.Then by analyzing the posterior distribution of model parameters,the verification results of model parameters,water output of some waterworks and the pressure of some nodes in the pipe network are given,which verifies the accuracy of the built hydraulic model.Secondly,the measures to alleviate the impact of superimposed water supply on municipal pressure are put forward.Then the water hammer pressure enveloping line is extended to the study of the applicability of superimposed pressure water supply.The time-delay free water pressure enveloping line is proposed for the first time and its important parameters are the minimum allowable pressure H_dmin,Based on the principle analysis of the maximum pressure fluctuationΔH_dmax,the H_dmin,ΔH_dmax in the main urban area of C city in a western province are determined to be 0.28 Mpa,0.1MPa.Then,based on the study of H_dmin andΔH_dmax,the criteria for selecting superposed water supply equipment and zoning of pressure variation in municipal water supply network are put forward.Finally,the municipal water supply pipe network is divided into pressure stable zone,fluctuating zone and fragile zone,which provides a reference for the selection of secondary water supply equipment.Thirdly,the"M"mode of water supply and the time period of water pressure peak and valley in the main urban area of western C city are studied.At the same time,the characteristics of free water pressure condition of water supply network in the main urban area are obtained:northwest high pressure,southeast low pressure,and the water pressure from northwest to southeast is gradually decreasing and then increasing.Then,according to the time-delay hydraulic calculation results,the time-delay free water pressure envelope of the four main pipes in the main urban area is made,and the water supply network in the main urban area is divided into stable pressure zone,fluctuating zone and fragile zone from line to surface.Finally,the pressure fluctuation zoning map of the water supply network in the main urban area of western C city is made,which is used as a reference for the selection of the laminated water supply equipment in the main urban area of western C city.Finally,the pressure robust zone and fluctuation zone around the application of superimposed water supply are discussed.In order to reduce the influence of superposed water supply on municipal pressure,the inverse proportion correlation between elevation and pressure fluctuation in main urban area was studied.Then the optimum setting height difference of steady flow tank and the numerical range of inlet pressure sensor are determined.In order to improve the energy saving of superimposed pressure water supply,the optimization measures of regulating volume of pressurized water tank for superimposed pressure water supply equipment are presented.Then the formula of energy saving rate of stack water supply is derived,and the type of centrifugal pump that should be selected is obtained.