弯道水流调整池对流态改善情况的数值模拟研究

发布时间：2018-01-02 19:00

本文关键词：弯道水流调整池对流态改善情况的数值模拟研究　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：在实际工程中减少弯道水流对凹岸的冲刷破坏、减弱弯道水流的横向环流以加快弯道后直道段的水流尽快回归平稳,是在工程设计中需要考虑的问题。对此,国内外的许多专家学者都做了大量的尝试。弯道水流调整池是一种调整效果好、结构体型简单、施工方便、易于维护的改善弯道水流流态的更有效措施。目前已经在南湾水库溢洪道尾水渠弯道上实施。但关于弯道水流调整池对弯道水流的调整规律性还有必要进行进一步研究,以便为同类工程应用提供设计依据。本文采用数值模拟的方法研究了弯道水流调整池相关参数的变化对弯道水流改善的效果影响及其尺寸优化。首先选用RNG k-?湍流模型,同时采用控制体积法离散控制方程,并使用VOF法追踪自由液面,对于压力场与速度场的计算本文采用PISO法。在此基础上本文主要做了以下工作1.对弯道水流调整池的可行性进行了研究;2.对同弯角度、不同纵向坡度的情况下,模拟了分析了弯道水流流态的变化,由此得到调整池在不同条件下对弯道横向水面比降的改善、消能、以及对横向环流翻滚情况的影响;3.通过模拟分析,同时结合实际工程的需要,选取适宜的参数变化区间,给出了改善效果较好的调整池参数。本论文的主要结论:1.弯道水流调整池无论是在改善自由液面坡降还是减轻液面的旋转翻滚情况均能达到一个较好的效果。2.弯道水流对调整池的深度要求不高,弯道纵向坡度越大,对调整池的深度越“敏感”。即弯道纵向坡度越大,实际需要的调整池深度可以适当的减小。3.弯道纵向坡度越大的弯道所需的弯道水流调整池长度越长。4.调整池的位置对弯道自由液面评价高度,也即对液面坡降改善的影响不大,通常位置因素只影响弯道横向环流情况。5.同纵坡坡度下弯道弯角的大小对最佳弯道水流调整池深度的选择区间的影响不大。6.同纵坡坡度下弯道弯角越大对弯道水流调整池最佳长度区间的需求通常越小。7.与常规消力池相比,弯道水流调整池的消能率较小。
[Abstract]:In the actual project to reduce the erosion of concave bend flow damage, transverse circulation weakened bend flow to speed up the curve after the straight section of the water as soon as possible to return to stable, need to be considered in engineering design problems. In this regard, many domestic and foreign experts and scholars have done a lot to try. Bend flow adjustment is a pool the adjustment effect is good, simple structure, convenient construction, easy maintenance and more effective measures to improve the flow pattern. The curve has been implemented in Nanwan Reservoir Spillway tailrace bend. But on the bend flow adjustment pool of bend flow adjustment rules as well as the need for further research, in order to provide design basis for the similar engineering changes. This paper studies the bend flow adjustment pool related parameters by using the numerical simulation method to improve the effect of bend flow and size optimization. First choice RNG K-? Turbulence model, and by using the control volume method to discrete the control equations, and tracking the free surface using the VOF method, for the calculation of the pressure field and velocity field by PISO method. On the basis of this paper mainly do the following work on the feasibility of 1. bend flow adjustment pool were studied; 2. of the same bending angle, different the vertical slope under the condition of simulated analysis of the change of the flow pattern of the curve, the adjustment pool under different conditions on the transverse surface slope improvement, energy dissipation, and the influence of the transverse circulation rolling; 3. by simulation analysis, combined with the actual needs of the project, select the suitable parameter ranges. To improve the pool better adjustment parameters are given. The main conclusions of this paper: 1. bend flow adjustment in both the rotary rolling pool to improve or reduce the level of free surface gradient can reach a The good effect of bend flow.2. to adjust the depth of the pool is not high, the greater the slope of the longitudinal curve, adjust the pool depth more "sensitive". That is, the greater the slope curve of vertical height adjustment, the actual needs of the pool depth can be reduced properly.3. bend longitudinal slope greater bend required bend flow adjustment pool the longer the length of the.4. adjustment pool position on the curve of free surface evaluation, namely to improve the level of the gradient has little effect, usually only affect the location factor has little effect on the.6. curve selection range of transverse circulation.5. with longitudinal slope under the curve bending angle on the optimum bend flow adjusting pool depth with longitudinal slope slope bend angle of the bend flow adjustment pool optimal length of interval demand is often less.7. compared with the conventional stilling pool, energy dissipation is smaller. Bend flow adjustment pool

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV135

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