急弯段闸孔出流的弯道水流特性研究

A study of bendway flow characteristics outflowing from sluice orifice on rapid river bend

  • 摘要: 在河弯处修建水工建筑物时,研究弯道水流特性对水工建筑物布置的影响十分重要。采用RNC κ ε紊流模型对急弯段闸孔出流的弯道水流进行了三维数值模拟。通过模拟计算,比较分析了急弯段不同闸位、不同流量条件下闸孔过流时的流速分布、紊流动能、压强分布和环流等相关水流特性与变化规律。分析研究结果表明,闸坝位于弯道上游时,弯道对闸坝过流的影响最小,但需对闸坝下流弯道凸岸岸坡附近区域采取一定的防护措施;闸坝布置在弯道中游时,过闸水流受弯道的影响最小,闸室水流的稳定性、闸门的工作安全以及闸墩的空蚀破坏都是实际工程中需要注意的重点。数值模拟验证与物理模型试验结果吻合较好,计算精度较高,能够满足相关计算研究要求。

     

    Abstract: Owing to the geologyical, topographical and hydrological factors, it is inevitable to build hydraulic structures in the river bend. So it is very important to carry out studies of influences given by the bendway flow on the layout of the hydraulic structures. The three dimensional numerical simulation of the bendway flow outflowing from the sluice orifices located on the rapid river bend has been made by using the RNC κ-ε turbulent model. With the aid of simulation calculation, a comparative analysis is made of the flow characteristics and variation law related to flow velocity distribution, turbulent kinetic energy and pressure distribution as well as circulation flow passing through the sluice under the conditions of different gate openings and different flow discharges. Analysis results show that as the dam sluice is located on the upper river bend, the influence given by the sluice on the flow passing through the dam sluice is the minimal, but some prevention measures should be taken for protecting the area close to the convex bank slope of the lower outlet bend against erosion; and the influence given by the river bend on the flow passing through the sluice is the maximal. Therefore, the stability of the flow flowing through the sluice chamber, the gate safety operation and the cavitation damage to the piers should be taken as the key points in consideration and to which more attention should be paid in practical engineering. The numerical simulation results, which are in good agreement with the results obtained from the physical model tests, can meet the requirements of the calculation studies.

     

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