Study On Optimization Of Flow Pattern In Forebay Of Pumping Station With Short Diversion Channel Combined With Sluice Gates

The layout of the combination of sluice and pump station was widely used because of its compact layout and taking up less ground,but this layout can easily complicate the flow field during the operation of the hydro-junction,thus causing bad flow patterns,it brings bad influence to the project operation.Therefore,it is necessary to study the flow pattern of pumping station with sluice gates.In order to optimize this flow field and to eliminate the bad flow pattern,this paper takes a gate station project in Zhejiang province as the research object,the flow field in the forebay and inlet pool of the pumping station with short diversion channel was studied by physical model test and numerical simulation.The main findings are as follows:（1）Based on the FLUENT computational fluid dynamics software,a numerical model of the research object was established using standard equation model according to the characteristics of water flow in the forebay of the pumping station with short diversion channels.The model can well show the flow field in the forebay and inlet of the pump station of short diversion channel combined with the sluice station.The numerical results are in good agreement with the model test results.（2）Through the numerical simulation and model test,the reasons of the bad flow pattern and the possible harm of the preliminary design scheme were analyzed.The main bad flow pattern is the deviation of the main flow in the forebay,there was a large area of backflow on the left side of the diversion wall,and the velocity distribution was uneven on the left and right sides of the inlet pool（3）A number of optimization schemes were proposed,including single rectification and combined rectification.The rectification effects of each scheme were comprehensively evaluated through qualitative comparison and quantitative analysis,the optimum rectification scheme（scheme 10）was selected as the recommended scheme.The feasibility of the recommended scheme is verified by the physical model test,and the velocity uniformity at the outlet section of the inlet pool is increased from 86.30%to 93.46%by the recommended scheme,the axial velocity deviation of both sides of the inlet pool decreased from 12.63%to 3.37%.The recommended rectification scheme has obvious effect,and can improve the flow pattern of the forebay and inlet pool of the pumping station in the short diversion channel（4）Based on the orthogonal test,the optimization of the opening arrangement of the diversion wall at the junction of the sluice station was carried out,and the optimum design parameters of the opening were obtained.When the side length of square orifice a,the distance between orifice b,the distance from orifice edge to diversion wall end c,the distance from orifice bottom edge to river bed h,and the length of diversion wall Lh are 0.9 d,0.6 d,0.8 d,0.15 h,and 9.8 d respectively,the forebay has the best flow pattern.（d is the inlet width of flow channel,and H is the underwater height of diversion wall）The research results have reference significance for the design,renewal and reconstruction of similar pumping stations.