阶梯式溢流坝过渡台阶消能特性研究

发布时间：2018-04-12 17:14

本文选题：阶梯式溢流坝 + 消能特性　；参考：《武汉大学》2017年硕士论文

【摘要】：溢洪道是水利枢纽中重要的泄水建筑物,绝大部分的水利工程为了防止并避免从坝面下泄的水流对河床和岸坡等的冲刷,都是通过溢洪道或溢流坝进行挑流消能,或者在坝体下游深挖河床修筑消力池或选用底流消能、跌流消能。阶梯式溢洪道、溢洪坝以其较高消能率而受到世界各国水利界人员的强烈关注。因此,加大对阶梯式溢流坝水流的研究,尤其过渡台阶布置形式对阶梯式溢流坝消能特性的影响研究,具有一定的科学研究意义和工程运用价值。本文针对阶梯式溢流坝过渡台阶布置形式对其消能特性的影响进行了模型试验研究,主要包括过坝水流流态、压强分布规律,阶梯式消能工消能率的计算,以及利用数值模拟方法对改善阶梯坝面水流不利流态的工程措施进行研究,取得的主要研究成果如下:(1)对阶梯式溢流坝消能率的基本理论进行了分析,明确了阶梯式溢流坝消能率的计算方式及其影响因素,为阶梯式溢流坝水流优化及消能优化提供理论依据。(2)结合某阶梯式溢流坝的具体结构布置,对现状布置下的水力特性进行了试验研究,分析可知在此布置下掺气起始点靠后,导致部分台阶处出现负压,这对溢流坝面运行存在不利影响。(3)对现状布置下的该溢流坝进行了数值模拟,分析发现掺气起始点随流量增大而向下游推移,这与模型试验的结论一致。针对这一不利因素提出了设置过渡台阶的优化方案,并对不同过渡台阶数的优化方案进行了数值模拟,通过对比分析初步拟定了最优优化方案。
[Abstract]:Spillway is an important water discharge structure in water conservancy project. In order to prevent and avoid the erosion of river bed and bank slope, most water conservancy projects use spillway or spillway to dissipate energy through spillway or spillway.Or in the dam downstream deep excavated river bed to build the stilling pool or select the bottom flow energy dissipation, falling energy dissipation.Therefore, it is of scientific significance and engineering value to study the flow of stepped spillway dam, especially the influence of the arrangement of transition steps on the energy dissipation characteristics of stepped spillway dam.In this paper, the influence of step arrangement on the energy dissipation characteristics of stepped spillway spillway is studied, which mainly includes the calculation of water flow, pressure distribution and the energy dissipation rate of step type energy dissipators.The numerical simulation method is also used to study the engineering measures to improve the flow unfavorable flow on the stepped dam surface. The main research results are as follows: 1) the basic theory of the energy dissipation rate of stepped spillway dam is analyzed.The calculation method of energy dissipation rate of stepped spillway dam and its influencing factors are defined, which provides a theoretical basis for the optimization of flow and energy dissipation of stepped spillway dam, and combines with the concrete structural arrangement of a stepped spillway dam.The hydraulic characteristics under the present arrangement are tested and studied, and the results show that under this arrangement, the initial point of air entrainment is backward, which results in negative pressure at some steps.It is found that the initial point of aeration moves downstream with the increase of flow rate, which is consistent with the conclusion of the model test.In view of this disadvantage, the optimization scheme of setting transition steps is put forward, and the optimization scheme of different transition steps is numerically simulated, and the optimal optimization scheme is preliminarily drawn up by comparison and analysis.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV651.1;TV135.2

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