Study On Flood Discharge Energy Dissipation And Aeration Mitigation Erosion Of A Water Conservancy Project

Water is an important guarantee for the survival and development of mankind.Although China has abundant water resources,it is extremely uneven in time and space.Therefore,China has built a large number of water conservancy projects for a long time.Safe flood discharge of water-releasing structures is the basis for ensuring the safety of water conservancy projects.Spillway and flood-discharging tunnel are two types of drainage structures commonly used.They can be utilized to vent extra floods over the planning reservoir capacity,ensure safe flood discharge,and prevent potential safety hazards.In this paper,the hydraulic characteristics of the step spillway and the flood-discharging tunnel,as well as the aeration mitigation erosion of the spillway tunnel,are studied for a pracical water conservancy project,including the physical model test and the numerical simulation methods.Through the aforementioned two types of research methods,the hydraulic characteristics of the step spillway are discussed,and its energy dissipation advantages when compared to the smooth spillway are also quantitatively demonstrated.Besides,the hydraulic characteristics of the flood-discharging tunnel are analyzed with the aid of the hydraulic model test,and the optimal erosion-mitigation scheme is proposed.The main contents and research results are as follows:(1)Summarized the research status of the spillway flooding energy dissipation and the aeration and erosion reduction of the spillway tunnel at home and abroad,focusing on the flow velocity distribution,pressure distribution,energy dissipation rate and the influence factors of aeration and erosion reduction in the spillway tunnel.Detailed research and summary.(2)Introduced the energy dissipation side of several water-dissipating buildings,and introduced the research method of the ladder efficiency rate in detail.The similarity relationship in the physical model test and the choice of the scale and the research method of the turbulent numerical simulation are introduced in detail.(3)Using ICEM CFD software for structured meshing,using FLUENT software to numerically simulate the step spillway and smooth spillway.The numerical calculation results of the step spillway are compared with the measured water surface line,flow velocity and pressure data of the step spillway to verify the reliability of the numerical calculation,and the distribution law of the flow velocity and pressure of the step spillway is given by analysis.By calculating the relative efficiency of the smooth spillway corresponding to the steppedspillway,the energy dissipation advantages of the stepped spillway are quantitatively analyzed.(4)Four schemes were introduced for the original design scheme of the flood model and the aeration and erosion reduction scheme for the hydraulic model test.The hydraulic characteristics of the spillway tunnel under the original design scheme were studied by measuring and monitoring the flow regime and hydraulic characteristics of each scheme.By comparing and analyzing the hydraulic characteristics of the flood discharge tunnel after adding the aeration and erosion reduction facilities,the water surface line along the process,the pressure distribution,the flow rate,the aeration concentration,the cavity length,the ventilation rate,etc.,the final conclusion is that it does not affect The optimal method for effectively reducing cavitation under the condition of raw water flow.Through the study of the spillway discharge energy dissipation and the aeration and erosion reduction characteristics of the spillway tunnel,the design parameters and theoretical basis are provided for the actual project implementation,which can be referenced and referenced by similar projects.