Research On Inlet Flow Characteristics Of Pumping Station Based On Different Inlet Flow Rates

The pump station inlet water flow rate is a key factor affecting the characteristics of the pump station inlet water flow.As the inlet water flow rate increases,the pump station inlet water flow gradually becomes turbulent,and different types of vortices are often generated near the water inlet.When the generated vortex reaches the suction The vortex time not only deteriorates the flow pattern of the inlet water of the pump station,but also reduces the operating efficiency of the unit,and even endangers the safe operation of the pump station.Previous studies on the inlet vortex mainly focused on the critical submergence depth of the inlet and the characteristics of the vortex.However,there are few studies on the influence of the inlet water velocity of the pumping station on the inlet vortex.This paper takes the yellow pumping station with two water intake structures(single-sided water intake structure and four-sided water intake structure)as the engineering background of the lower Yellow River.The relationship between the inlet vortex characteristics and the inlet water flow rate was studied.1.The classification and hazards of inlet vortices are explained,and the current research status of inlet vortices generation conditions and vortex elimination measures at home and abroad are reviewed from the three aspects of numerical simulation,experimental research and submerged water depth,and the impact of inlet vortices is analyzed.The main factors of water vortex and the significance of research.2.Theoretically explain the control equations,grid division and application conditions of the three-dimensional turbulence model used in the numerical simulation of the pump station inlet flow characteristics;analyze the pump station inlet flow characteristics with two inlet structures,and propose The numerical calculation uses the unsteady SST k-ω model and the VOF model to solve the three-dimensional turbulence problem of the inflow of the pumping station,which can better numerically simulate the flow pattern,vortex distribution and shape of the inflow,and can be used to analyze the characteristics of the inflow of the pumping station.the study.3.Taking the inlet water depth as the control parameter,numerically simulate the influence of different inlet water flow rates on the inlet water flow characteristics of the pumping station with two inlet structures.The inlet forepool and the inlet sluice of the pump station with single-face inlet structure are respectively simulated.The water flow characteristics of the front pool and inlet pool of the pumping station with the chamber and the four-sided inlet structure are analyzed;the focus is on the flow rate of the pumping station and the law of the generation and development of the vortex on the inlet surface.The vortex distribution and the vorticity distribution of the inlet section and the vorticity value are analyzed from the angles of the characteristics of the surface vortex of the inlet water,revealing the law that the strength of the surface vortex gradually increases with the increase of the inlet water velocity,and dividing the different inlet velocity and surface The corresponding relationship between the vortex types is basically the same after comparing with the corresponding model test results.4.Through numerical simulation and experimental research on the characteristics of the inlet flow of the pumping station with two inlet structures,the distribution characteristics of the inlet flow pattern of the pumping station with two inlet structures and its influence on the inlet vortex are analyzed.The results show that the inlet flow pattern of the pumping station with single-sided inlet structure is relatively turbulent in the surface water body of the inlet and the water body near the upper edge of the inlet of the flow channel.The inlet flow pattern in other water bodies is relatively smooth,and the inlet vortex is generated in the surface water body.And development;the inflow state of the pumping station with four-sided intake structure is not only turbulent in the surface water body,but also in the water body behind the inlet pipe and the lower part of the inlet bell mouth.Therefore,the inflow vortex is not only generated in the surface water body.It develops and produces and develops water vortices(wall vortex and bottom vortex)in the water body behind the inlet pipe and the lower part of the inlet bell mouth.5.Based on the analysis of the influence of the type of vortex on the inlet water surface on the characteristics of the inlet water flow and the different degree of harm,the inlet flow velocity value to ensure a good inlet flow state of the pump station is proposed.For pump station projects with single-sided water intake structure,the inlet water flow rate should not be greater than 0.349m/s;for pump station projects with four-sided water intake structure,the inlet water flow rate should not be greater than 0.322m/s.Using the method of combining numerical simulation and model test,the law of the generation and development of the vortex on the inlet surface of the pumping station is revealed by the influent flow rate,and the inlet flow rate value that can ensure the good influent flow state of the pumping station is proposed,which can be used for the pumping station project.The design and safe operation of the company provide theoretical basis and technical support.