Numerical study on the performance of bulb turbine by using runaway condition to flood discharge and sediment dredging

27th IAHR Symposium on Hydraulic Machinery and Systems

Yaping, Z.^1 ; Weili, L.^1 ; Zhihua, L.^2 ; Hui, R.^1 ; Xingqi, L.^1

Institute of Water Resources and Hydro-Electric Engineering, Xi'An University of Technology, Xi'an, Shaanxi Province, China^1

Xi'An Thermal Power Research Institute Co., Ltd, Xi'an, Shaanxi Province, China^2

关键词: Flood discharge;    Flow charac-teristics;    Normal operations;    Outlet velocities;    Runaway conditions;    Sediment flushing;    Three-dimensional numerical studies;    Tubular types;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/5/052018/pdf
DOI  :  10.1088/1755-1315/22/5/052018

来源: IOP

【 摘 要 】

When the floodwater of the bulb tubular type power station is released, a large number of sediment carried by the flood silts up at outlet of the tube, and has a serious impact on the later normal operation of the power station. In order to solve this problem, this paper presents a method that treats the tube sluice as the energy dissipation facility, use the small opening runaway conditions to carry out a regular and short time sediment flush during discharge, and set the sediment self-flushing corridor in the downstream river to achieve sediment flushing and dredging. Unsteady three-dimensional numerical study which considers free-surface of the Reservoir for different tube sluice conditions is conducted to reveal the flow capacity of the turbine and the flow characteristics in the draft tube. In particular, through analyzing the flow characteristics in the tube, the maximum particle size of the sand that can be washed away can be determined, assuming the outlet velocity of the tube is the starting speed, and then the sediment flushing capability of the turbine can also be estimated. The results show that: using the runaway conditions for flood discharge and dropping the height of the tube sluice to achieve the purpose of energy dissipation not only can improve the flood discharge capacity of the power plant, but also can increase flushing distance at the tailrace, and thus enhance the ability to remove silt. Setting the sediment self-flushing corridor at the downstream river would be a good solution to tailrace siltation problems of the bulb turbine.