【作者】 曾丹；

【导师】 杨磊；

【作者基本信息】 武汉大学 ， 水工结构工程， 2017， 硕士

【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。更多还原

【Abstract】 As the important discharge structure in hydro-junction,in order to prevent and avoid the water flow from the dam surface erosion of the riverbed and the slop,majority of hydraulic engineering are adopted spillway to dissipate energy or are built stilling basin.Stepped spillway have been drawn widely interest by because of high energy dissipation.Especially the study of energy dissipation characteristics of transitional steps of stepped spillway that have great scientific significance and engineering application value.Based on the stepped spillway,this paper adopts theoretical analysis,model test research and numerical simulation to research the effects of transitional steps on dissipation characteristics of stepped spillway,the main research result is as follows.(1)Conclude the basic theory on the dissipation characteristics of stepped spillway,make clear the reason and improving engineering of unfavorable flow,in order to provide theory support for optimization scheme of stepped spillway.(2)The model test was designed based on the structural arrangement of stepped spillway and analyzed the hydraulic characteristics.The result of the test showed aeration starting point was relatively backward,and the pressure of some steps was negative which was unfavorable to spillway surface.Aiming at the(3)Based on the structural arrangement of stepped spillway,numerical simulation was adopted to analyze the dissipation characteristics.It was found that the aeration starting point was relatively backward which was consistent with the conclusion of the model test.Aiming at the unfavorable factor that aeration starting point was relatively backward,optimization scheme of setting the transition step was proposed,and numerical simulation was adopted to analyze the schemes of different transition steps.The optimal optimization scheme was developed after the analysis were compared.更多还原