Analysis Of Influent Flow State Of Baiqu Port Pumping Station And Research On Improvement Measures

The connecting section of channel and inlet passage(inlet sump)is the forebay.The function of the forebay is to adjust the water flow of canal,and smoothly deliver the water flow to the inlet passage,so as to improve the water absorption conditions for the pump.When the design of the forebay is unreasonable,there will be a large area of backflow area in the forebay,which provides poor flow conditions for the inlet passage.Jiangyin Baiqugang Pumping Station is a gate-station combined two-way flow pssssage pumping station.When the pumping station is running,there is a large area of return flow near the control gate,which seriously affects the efficiency of the unit.In this paper,through the three-dimensional numerical simulation method,the research on the influent flow state of Jiangyin Baiqugang Pumping Station and its improvement measures is carried out.The research results are of great significance for improving the stability of the pumping station.(1)Numerical simulation was used to analyze the design operating water level and the highest operating water level of the forebay of Baiqugang Pumping Station.The research shows that there is a large-scale backflow area near the forebay pier,and the backflow develops from the surface layer to the bottom layer,which is serious.It affects the flow state of the outlet section of the forebay,and the water inlet conditions of the water inlet passage are poor.There is a large area of attached vortex on the top layer of the inlet flow channel,which leads to poor inlet conditions of the pump.(2)Using the orthogonal test method,numerical simulation was used to analyze the influence of the flow regime improvement measures—the geometrical parameters of the perforated diversion piers on the flow regime of the pumping station forebay.The research shows that the perforated diversion pier eliminates the large-scale backflow area near the pier and improves the uniformity of the flow velocity in the forebay.(3)The improvement effect of the combined diversion pier measures on the influent flow state of the pump station under the design operating water level is studied and analyzed.By extending the straight piers between the inlet passages,the attached top vortex existing on the surface of the channels is reduced,and the flow pattern flowing into the inlet passages is smooth;The existing surface vortex and the backflow area in the dead water area;by adding an arc-shaped diversion pier before the inlet of the water inlet passage,and optimizing the straight pier between the channels to an arc-shaped diversion pier,the water flow in the pool can be smoothed according to the situation.,eliminates the vortex near the straight pier and the top layer of the flow channel,and improves the uniformity of the flow velocity distribution.The arrangement of the above-mentioned combined diversion piers improves the flow pattern of the pumping station forebay and the inlet flow channel,smooth the water flow in the inlet flow channel,eliminates bad flow patterns such as vortices in the flow channel,and improves the uniformity of the flow rate distribution of the pump inlet water.(4)The influence of the combined measures of "opening diversion pier+combined diversion pier" on the flow state of the pumping station forebay and the inlet passage under the highest operating water level was studied and analyzed.The bad flow pattern on the outlet side and in the water inlet passage basically disappears,and the water flow is smooth.Compared with the original scheme,the velocity uniformity of the outlet section of the forebay is increased by 37.20%,and the velocity-weighted average angle is increased by 12.04°.The flow velocity uniformity of the cross-section before the outlet of the inlet passage is increased by 35.61%,and the velocity-weighted average angle is increased by 1.53°.