Study On Silt Deposition And Anti-siltation Measures In Pumping Stations Of Sediment-laden Rivers

Pumping stations are important water conservancy projects.For pumping stations that take water from high-silt rivers,sedimentation is a serious problem that plagues their operation and management.The sedimentation in the front pool of the pumping station is mainly related to the flow velocity and flow pattern in the fore pool and the sediment content of the river itself.The flow velocity and flow pattern in the fore pool can be improved by rectification measures to reduce sedimentation.The Dayuzhang Pumping Station is an important part of the Yellow River to Qinghai Water Diversion Project,and the pumping station has serious sedimentation.This paper takes the Dayuzhang Pumping Station as the research object,carries out the numerical simulation of the clean water conditions and the muddy water conditions,and compares with the field survey results,analyzes the siltation forms and causes of the siltation in the front pool of the pumping station.A variety of anti-siltation measures have been proposed for the front pool of Dayuzhang Pumping Station,and a variety of numerical simulations of clean water and muddy water have been carried out for different anti-siltation measures,so as to determine the optimal anti-siltation measures and compare them through numerical simulations.The optimal inlet channel form of the pumping station in the sediment-laden river and the performance of the pump device under the sandy water medium are analyzed.The research conclusions of this paper are as follows:(1)The sedimentation in the forepool of Dayuzhang Pumping Station is serious.The main reason is that when there are fewer units to start,the forepool has a low flow rate and the flow rate is less than the non-siltated flow rate;the sedimentation is mainly concentrated on both sides of the forepool and appears almost The state of axial symmetry,in addition,there is a large sedimentation in the inlet flow channel,which seriously affects the water diversion of the pumping station.(2)Through numerical analysis,there is a large amount of backflow in the diffusion section of the front basin and the inlet flow channel of the unstarted unit of the Dayuzhang Pumping Station,forming a low-speed zone.The backflow area of the front pond and the area with high sediment concentration are basically the same as the main sedimentation areas of the field survey,which proves that the return flow and low-velocity dead water area are important reasons for the sedimentation.(3)Proposed a front-separated forebay scheme at the front of the diversion pier,and numerically simulates the sedimentation pattern and the flow pattern of the water in the forebay under various combinations of start-ups.The results show that compared with asymmetrical startup,the symmetrical startup has less backflow in the front pool and better flow regime;under various startup combinations,the split fore pool solution can significantly reduce the sedimentation in the front pool compared to the current solution.(4)The feasibility of four different anti-forepool siltation measures was studied.Numerical calculation results show that the 45° pressure plate of the Dayuzhang Pumping Station can greatly improve the flow pattern of the forebay and reduce sedimentation;increasing the slope and compressing the inlet flow channel have limited improvement effects on the flow pattern of the forebay;setting a triangular jet bottom The ridges and diamond-shaped diversion piers have inferior effects to the forepool sedimentation control effect than the 45° pressure plate.(5)The adaptability of the elbow-shaped,bell-shaped and dustpan-shaped inlet channels of the pumping station in the pumping station of the river with sediment-laden is compared.Numerical simulation results show that the elbow-shaped inlet channel is more suitable for the pumping station of the river with sediment than the dustpan-shaped inlet channel and the bell-shaped inlet channel.(6)Discussed the impact of sandy water flow on the performance of the pump device.Numerical calculation results show that the sediment particles will cause the overall performance of the pump device to degrade,shift the high-efficiency point to a small flow rate,and the sedimentation in the inlet flow channel varies little with the operating point.The sediment in the front pool of the pumping station should be focused on.Siltation.