表孔、底孔联合泄洪流场数值模拟与冲刷趋势分析

发布时间：2018-02-16 13:13

本文关键词： 数值模拟底流消能体型优化次跌落冲刷趋势　出处：《四川大学学报(工程科学版)》2016年03期 　论文类型：期刊论文

【摘要】：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。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k-ε湍流模型、VOF自由表面捕捉技术,对其联合泄洪3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。结果表明:原设计方案消力池内水流波动大,流场紊乱,出池水流2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,保留底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2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。可见,在局部冲刷模拟还很不成熟的情况下,可以采用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]:In order to optimize the configuration and layout of the drainage structure and to explore the relationship between the flow field distribution and the local scour of the downstream riverbed, the physical model experiment of a large hydropower station table and bottom hole flood discharge facility is carried out. Based on the standard k- 蔚 turbulence model and VOF free surface capture technique, the 3D flow field of the combined flood discharge is numerically simulated, and the flow velocity and water surface line in the surface, bottom hole and stilling pool of the surface-hole overflow dam are obtained. Hydraulic characteristics such as pressure. By comparing with the results of hydraulic model test, the correlation mechanism between the flow field structure and the erosion form of the downstream channel is analyzed. The results show that the flow in the stilling pool of the original design has a large fluctuation of water flow and a disturbance of the flow field. In the corresponding physical model, serious scour occurred in the downstream, the most serious right bank slope and the left guide wall downstream of the surface hole. By improving the shape of the stilling pool and retaining the construction of diversion wall between the bottom hole and the surface hole, the flow pattern of the stilling pool and the outlet pool has been significantly improved, and the flow of the outlet pool has been reduced twice. The degree of submergence is greatly weakened, the horizontal diffusion of the main stream of the outlet pool is relatively sufficient, and the lateral compression is restrained sufficiently. Accordingly, the range and depth of the river bed scour are greatly reduced. In particular, there is almost no erosion in the right bank area corresponding to the bottom side of the original scheme. It can be seen that under the condition that the local scour simulation is still very immature, the method based on the flow field analysis can be used to carry out the trend analysis of the downstream riverbed scour. And then guide the layout and shape optimization of the drainage structure.
【作者单位】：西安理工大学西北旱区生态水利工程国家重点实验室培育基地;
【基金】：国家自然科学基金资助项目(51579206) 水利部公益性行业科技专项经费项目资助(201301063) 国家重点实验室培育基地自主研究项目(ZZKT-1)
【分类号】：TV135.2

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