Research On Optimum Design For The Inlet And Outlet Passage Of Low Head Pumping Stations

The Middle Route Project of South-to-North Water Diversion,as a significant and strategic project to relieve the serious water shortage in Northern China,began to deliver water to Beijing City,after the flood season in 2014.Prior to completion of the auxiliary projects in provinces along the route,the amount of water received,is not reaching the predetermined scale.So,surplus water can be delivered to Beijing City,located at the end of the diversion project.On this basis,Miyun Reservoir Regulation and Storage Project for Incoming Water from South-to-North Water Diversion is put forward to ensure the stability and effective reception of incoming water,and to solve the problem of mismatch between the consumption of Beijing City and the inflow from Danjiangkou Reservoir.Meanwhile,Miyun Reservoir,which is almost dried up,may play storage efficiency.And the incoming water also can be delivered to each new town in districts of Beijing,thus creating further benefits.Through the constructions of cascade pumping stations,the Regulation and Storage Project can deliver the incoming water to Miyun Reservoir by the existing Beijing-Miyun Water Diversion Canal.Facing the large discharge and cascade pumping,how to increase efficiency,to reduce energy consumption,to minimize operation cost and to maximize benefit by technical methods and reasonable design,need to be studied.Axial flow pumps and mixed flow pumps with large discharge and low head,are used at the 7 new downstream stations.In order to achieve the optimal system efficiency of pump installations and to reduce energy consumption and operation cost,not only the type and dimension of inlet and outlet passages must be studied,but also reasonable design need to be suggested.After inlet and outlet passage design based on experience,we will build models,perform numerical simulations by CFD,analyze and predict the performance of passages,further optimize design,and then make the structure and dimension of the passages more reasonable.Around the turbulent flow characteristics inside them,this article adopts methods of numerical simulation and physical model test,optimization design and research the inlet and outlet passages of low head pumping stations.In this research,based on unsteady continuity equation and Navier-Stokes equation,we will predict the performance and optimize the design of the installations,through simulating the flow inside the passages of pump installations and impellers by Fluent,the most widely used CFD software worldwide.Meanwhile,through carrying out the physical model test and efficiency testing(energy testing)of the installations,we can validate and accredit the results of numerical simulation.By analysising and contrasting the results from numerical simulation and physical model test,we can draw a conclusion that through assembling elbow inlet,siphon outlet and axial flow pumps or mixed flow pumps with large discharge and low head,the efficiency of pump installations can reach the requirements expected,to provide a strong basis for pumping station design.