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Numerical Simulation Study of Surface Outlet and Bottom Outlet Joint Flood Discharge Energy Dissipationand Scour Trend Analysis
(Xi’an Univ. of Technol)
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投稿时间:2015-07-23    修订日期:2016-03-23
中文摘要: 摘 要: 【目的】为了优化泄水建筑物的体型与布置方案,探索流场分布与下游河床局部冲刷间的关联性。【方法】结合某大型水电站表、底孔泄洪设施的物理模型实验,基于标准 湍流模型、VOF自由表面捕捉技术,对其联合泄洪三维流场进行数值模拟研究,获得了表孔溢流坝面,底孔及消力池内的流速,水面线,压力等水力特性。通过与水工模型试验结果对比,分析流场结构与下游河道冲刷形态间的关联机制。【结果】结果表明:原设计方案消力池内水流波动大,流场紊乱,出池水流二次跌落大且主流下潜河床,横向扩散不充分。相应的物理模型上,下游发生了严重的冲刷,冲刷最严重的右岸岸坡及表孔左导墙下游,恰好是右岸主流贴岸及左岸回流压迫区。通过改进消力池体型,保留低孔与表孔消力池间施工导流墙等措施,显著改善了消力池及出池流态,出池水流二次跌落减小,下潜程度大为减弱,出池主流水平扩散较为充分,横向挤压等得到充分的抑制。相应地河床冲刷的范围及深度均大为减小,特别是原方案底孔侧对应右岸区域几乎没有发生冲刷。【结论】可见,在局部冲刷模拟还很不成熟的情况下,可以基于流场分析的办法对下游河床冲刷进行趋势性分析,进而指导泄水建筑物的布置与体型优化。
Abstract:Abstract:【Objective】In order to optimize the size and layout of discharge structure, explore the relevance between flow field distribution and local scour of the river bed.【method】Physical experiments in a large-scale hydropower station surface and bottom joint flood discharge facilities based, used standard turbulence model and VOF free surface capture technology, three dimensional flow field of the combined flood was numerical simulated , obtained the flow velocity ,water line and pressure hydraulic characteristics of the surface orifice spillway, bottom outlet and the pond. By comparing with the experimental results of hydraulic model, the correlation mechanism between the flow field structure and the downstream channel scour pattern was analyzed.【Result】Results show that: the original design of the stilling pool water fluctuation, flow disorder, pool water secondary sag and mainstream dive riverbed, lateral diffusion is not sufficient. The corresponding physical model, which occurs serious erosion in the downstream. Erosion is the most serious on the right bank and behind the left guide wall of surface hole, is just on the right bank of the mainstream posted shore and left back pressure area. Through improved the shape of the plunge pool with the methods of retaining the construction diversion wall between low porosity and surface hole stilling pools and so on, significantly improved the flow regime of stilling basin, the pool water secondary drop decreases, dive is weakened, a pool level of the mainstream diffusion more fully, lateral extrusion can be suppressed sufficiently. Accordingly, the scope and depth of the riverbed erosion are greatly reduced, especially on the right bank side corresponds to the original proposal prepared hole area almost no erosion occurs.【Conclusion】Obviously, in the simulation of local scour is still not mature , based on flow field analysis method for trend analysis of riverbed scouring, layout and shape optimization and direct discharge structure is feasible.
文章编号:201500731     中图分类号:    文献标志码:
lishanshan,Li guodong.Numerical Simulation Study of Surface Outlet and Bottom Outlet Joint Flood Discharge Energy Dissipationand Scour Trend Analysis[J].Advanced Engineering Sciences,2016,48(3):26-34.