【作者】 刘超；

【导师】 杨永全；

【作者基本信息】 四川大学 ， 水力学及河流动力学， 2006， 博士

【摘要】 龙抬头式泄洪洞在中、高水头的水利水电工程中应用十分普遍，其突出的水力学问题是反弧段的空蚀破坏，反弧段空蚀破坏的部位常见于反弧末端、反弧段下游底板和反弧段下游侧墙。为了减免泄洪洞的空蚀破坏，一般采用底部进气的掺气设施。我国大型龙抬头泄洪洞运行表明，采用常规的底部进气的掺气设施后，反弧段下游侧墙仍可能出现空蚀破坏，这提出了两个值得研究的重要问题：采用常规掺气减蚀设施后，大型龙抬头泄洪洞反弧段下游侧墙为什么仍会出现空蚀破坏，采取何种措施才能有效地减免反弧段下游侧墙的空蚀破坏。大型龙抬头泄洪洞反弧段下游一般均具有流速高、单宽流量大、佛氏数低、底坡小的特征，使其掺气减蚀设施体型设计有较大困难，反弧末端的掺气设施，由于水流受反弧段离心力的影响，其体型设计的难度更大，如何优化小底坡、低佛氏数泄洪洞上的掺气设施体型，这也是值得研究的问题。 本文在总结前人研究成果的基础上，采用大比尺的模型试验，结合紊流数值模拟，分析了采用常规掺气减蚀设施后，大型龙抬头泄洪洞反弧段下游侧墙仍可能出现空蚀破坏的原因；首次提出了解决泄洪侧墙空蚀破坏的侧墙掺气方案；从三维角度提出了小低坡、低佛氏数泄洪洞掺气坎体型优化设计的一些建议。主要研究内容和成果如下： (1)试验研究表明，采用常规的掺气设施后，反弧段下游边墙仍容易空蚀破坏的原因主要在于：反弧末端采用常规的底部掺气设施后，掺气坎后的出射水流，其底部受掺气空腔的影响，压强接近于空腔负压，其顶部与洞顶余幅中的气流相接，其压强接近大气压强，空腔段边壁处动水压强小，水流空化数很更多还原

【Abstract】 Ogee spillway tunnels are widely used in middle or high head water conservancy and hydropower projects. Its main problem in projects is cavitation damage of ogee section, which can be frequently found in the end, downstream baseboard and downstream sidewalls of ogee section. The aerators are normally designed to inhale air from the bottom to slove this problem. According to operation of projects, the cavitation damage still exists at downstream sidewalls of the ogee section despite using this normal aerators. What we need to study are: why do the cavitation damage still exist and what kind of measure can alleviate it effectively. Since the downstream flow of ogee section in large spillway tunnel is normally characterized by high speed, large discharge, low Fr and slight slope of the channel, it is difficult to design the shape of aerators to alleviate cavitations. The influence of centrifugal force on the flow at the end of ogee section makes the design work more difficult. It is significant to study how to optimize the shape of aerators for this kind of spillway tunnel.Based on large-scale model experiments and numerical simulation of turbulent flow, the reasons of caviation damage, which still exist after using normal aerators, were analyzed in this paper. The air entrainment plans of solving cavitation damage for downstream sidewalls of ogee section were also discussed. In addition, some suggestions optimizing the shape of areators in slight slope of the channel and low Fr更多还原