Numerical Simulation and Experimental Research on the Sand Removal Efficiency of a Swirling Sand Removal Device
In order to improve the sediment removal efficiency of sediment removal tunnels in reservoir,we have developed a new type of swirl sediment removal device.In this paper,the different combinations of impellers in swirl sediment removal device,the velocity distribu-tion of swirl flow field,and the influence of swirl flow device on the scouring and silting characteristics and the efficiency of sediment removal at the mouth of a sand drainage tunnel are studied by numerical simulation and hydraulic model test.The numerical simulation results show that the flow field range of the single impeller in the swirl sand removal device expands with the increase of the rotational speed,but the flow field range does not increase when the rotational speed of the impeller increases to 20 r/s.The range of swirl flow field after the combination of multiple impels in the swirl sand removal device depends on the rotational speed of the impels and their arrangement.When the swirl sand re-moval device is arranged in a triangular manner,the range of the combined swirl flow field also expands with the increase of the rotational speed of each impeller.However,too small arrangement distance between impeller groups will lead to too high energy dissipation,and too large arrangement distance between impeller groups can not form an effective combined swirl field.The optimal operating state of swirl sand removal device is that the distance between impeller groups is 70 mm and the rotating speed of impeller is 20 r/s.The results of numerical sim-ulation and hydraulic model test show that the swirl sand removal device can effectively increase the sand removal efficiency of the tunnel and the range of strong scouring and silting.When the reservoir water level is deep and the silting form is a scouring funnel,the swirl sand remov-al device can increase the efficiency of the tunnel by 71.5%;When the reservoir water level is shallow and the form of sediment deposition is a sand flushing corridor,the swirl sediment removal device can increase the sediment discharge capacity of the tunnel by 4.02 kg,indicating that the device has a better removal effect on the sediment deposition in the reservoir with shallow water depth.It is of great significance to solve the problem of sediment deposition in Hexi reservoir with less water and more sediment in Gansu province.
numerical simulationhydraulic model experimentsediment discharge in reservoir areaswirling flow field
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维普
