Study On Optimum Hydraulic Design And Model Experiment For Inlet And Outlet Conduits Of Baoying Pumping Station

Baoying pumping station is one of the source projects of the East-Route South-to-North Water Transfer. It works more than 5000 hours every year, based on which, to increase efficiency of the pump system is the most important work for its design.After signing a contract of pump equipment for the station, Japanese Hitachi Company put forward its design of inlet and outlet conduits of the station. For low-head pumping stations such as Baoying pumping station, hydraulic designs of inlet and outlet conduits have obviously influence on performance of pump system. Therefore, in order to examine hydraulic performance of the conduits and to ensure high efficiency of the pump system, optimum calculations and model experiments are carried out on Baoying pumping station.At present, both integrate model experiment and disintegrate model experiment could be used to study pump system. Integrate model experiment is usually applied to get hydraulic performance of a pump system. However, it is hard to gain and improve performance of every part, which composes a pump system. Thus, disintegrate model experiment is used to research the inlet and outlet conduits of Baoying pumping station. Because a pump system consists of a pump, inlet and outlet conduits, efficiency of the pump system should be a comprehensive target including the pump efficiency and conduit efficiency. What is more, the pump system with excellent hydraulic characteristic should be contributed to by a pump with excellent hydraulic characteristic and conduits with fine flow patterns. Disintegrate model experiment is obviously convenient to compare and optimize the every part performance. In this way, the hydraulic performance of pump system could be optimized.On the basis of numerical simulation of 3D turbulent flow, flow patterns of the inlet and outlet conduits are simulated respectively. Control equations of numericalsimulation include continuity equation and Reynolds Navier-Stokes equation with standard k - e turbulent model. The Finite-Volume-Method is utilized for discretization of the control equations. SIMPLE algorithm is applied to pressure-velocity coupling based on the staggered grid system.Based on methods mentioned above, an optimum design is applied for inlet and outlet conduits of Baoying pumping station. The train of thought is to finish series calculation of flow corresponding to different boundaries and try the best to make these boundaries optimal. Objects of optimum design for inlet and outlet conduits are defined respectively: the object of inlet conduit is to optimize two object functions and minimize hydraulic loss without vortex or other bad flow patterns in the conduit and the object of outlet conduit is to take back kinetic energy as much as possible to minimize hydraulic loss without flow separation.In order to compare the scheme of Hitachi company with the optimum scheme of this paper and to verify the results of numerical simulation and optimum design to meet the needs of Baoying pumping station, model tests are carried out by observing flow patterns and measuring hydraulic losses.Model experiment results indicate that not only numerical simulation results of this paper are consistent with them, but also the optimum scheme is more superior to the scheme of Hitachi Company in both flow patterns and hydraulic losses.Therefore, conclusions could be drawn that the numerical simulation results are correct and the optimum design method combining disintegrate model experiment with numerical simulation is feasible. Furthermore, the optimum design method, mainly by means of numerical simulation supplemented by means of model experiment, could be used as reference for other large pumping stations of the East-Route South-to-North Water Transfer.