Study On The Configuration Of Diversion And Flood Discharge Structure Of Maling Hydropower Project

Maling water conservancy project has a narrow terrain,so,the energy dissipation space is limited,and the hydraulics problem is complicated.Construction diversion period,the operation of the diversion tunnel affects the measure during flood season and the construction of the building.During the period,the inlet configuration of diversion tunnel has a certain influence on the flow regime,and the change of flow regime directly affects the flow hydraulic Parameters of diversion tunnel.Therefore,it is necessary to study the inlet conformation of diversion tunnel.During the operation period,when the discharge flow is large,the concentric concentration problem may be generated.If the conformation of energy dissipator is different,the energy distribution of the water outlet hole will be different,as well as the downstream scour depth.In this paper,the Mailing water conservancy project is taken as the research object.In order to study the influence of energy dissipator,in order to optimize the layout of hydraulic structures,based on the model test,the paper used numerical simulation to calculate the flow field of the hydraulic structures under different type.The flow field of the diversion tunnel is simulated by FLUENT software,and the calculated flow field data are basically consistent with the model test results,such as the data of pressure.The research found that if the imported roof curve smoothly convergence,it will be beneficial to reduce the phenomenon of water shedding,therefore,the design of boundary connection should try to satisfy the principle of tangency,in order to reduce the effect of inflection point.The effect of the sectional shape on the flow regime is more pronounced,compared to the city gate-type section,the type of rectangular section brings weaker flow shedding and less energy loss,at the same time,the possibility of cavitation in the gate slot can be reduced.After comprehensive comparison,the paper considers that the scheme of rectangular section is better.The flow field of the drain hole in dam-body is simulated by FLOW-3D software,and the numerical results can basically reflect the flow field information.Under large-single-wide flow,the water tongue diffusion of narrow slit type bucket is limited,bring about energy concentration,and the high differential type bucket will leads to batter situation.Further analysis of energy dissipation mechanism,the high differential type bucket have following advantages.The flow is highly turbulent,the role of downstream water cushion is strong,and energy dissipation is large.The average impact pressure is small and dispersed,The distribution of pressure fluctuationsis equally dispersed,spectrum analysis found that most of its energy concentrated in the low frequency region.The advantages of the conformation can be preserved at the time of combined flood discharge.