| The pump sump is an important intake building,and its main function is to further adjust the flow from the Forebay.If the water flow pattern in the pump sumps is bad,even there are vortices,it will not only significantly reduce the operation efficiency of the pump,but also may lead to the vibration of the pump unit,unable to work.Therefore,it is very important to improve the inflow flow pattern of the pump sumps through the corresponding rectification measures.In this paper,the comprehensive rectification facilities are used to rectify the inlet pool of the pumping station combined with the gate station,and the cross vortex elimination plate is designed by the method of orthogonal test,and the numerical simulation is carried out for different parameter combinations,so as to obtain the general law of improving the bad flow pattern of the inlet pool.Firstly,a three-dimensional model is established,and two working conditions are explored in this paper,i.e.the designed operating water level is 1.5m and the low water level of the outer river is 1.0m.By analyzing the flow pattern of the original scheme under two conditions,it is found that the flow pattern of the forebay is better,but after entering the inlet pool,the forward flow near the pier of the gate station has backflow and vortex,and the flow pattern in the backflow area is disordered.Then,a diversion pier is added to the forebay to extend the length of the diaphragm pier,so as to improve the flow pattern of the inlet pool.After determining the optimal length of the diversion pier,the parameters of the cross vortex elimination plate are optimized by orthogonal test.The design factors include the width of the upper edge,the width of the lower edge,the height of the lower base and the overall height of the cross vortex elimination plate.By using L16(45)orthogonal table and analyzing the test indexes,the optimal parameter scheme under the comprehensive rectification measures is selected.Finally,through the analysis of the results of two rounds of orthogonal test,the optimal parameter combination under the comprehensive rectification facilities is summarized.For the design operation water level and the low water level of the outer river,when the length of the diversion pier is 3D,the width of the upper edge of the cross vortex elimination plate is 60mm,the width of the lower edge is 1200mm,the height of the lower base is 60mm,and the overall height is 160mm,the flow pattern of the inlet pool is the best.At this time,the velocity uniformity of the inlet section of the designed operating water level is 80.17%,which is 5.88%higher than the original scheme;the weighted average angle is 82.90°,which is 2.83° higher than the original scheme;the velocity uniformity of the bell mouth section is 59.08%,which is 0.49%higher than the original scheme;the weighted average angle is 67.16°,which is 3.03° higher than the original scheme.The results show that the velocity uniformity of the low water level inlet section of the outer river is 75.11%,which is 2.73 percentage points higher than the original scheme;the weighted average angle is 81.48° which is 1.13° higher than the original scheme;the velocity uniformity of the bell mouth section is 59.88%,which is 2.31 percentage points higher than the original scheme;the weighted average angle is 64.78 ° which is 1.43 ° higher than the original schemeThrough the numerical simulation and orthogonal experimental design,the optimal parameter combination under the comprehensive rectification measures is obtained,which proves that it is reasonable and feasible in improving the bad flow pattern of the inlet pool of the pumping station combined with the gate station.The research results have a certain reference value for the multi parameter optimization and design in the engineering design of the pumping station combined with the gate station. |
