高水头泄洪隧洞水力特性试验及数值模拟研究

发布时间：2018-04-30 01:29

本文选题：泄洪隧洞 + 龙抬头　；参考：《天津大学》2014年硕士论文

【摘要】：泄洪隧洞是水利水电工程中常见的泄水建筑物型式之一。国内外已经出现很多由于泄洪洞体型设计不当导致泄水建筑发生破坏的案例，因此对泄洪隧洞水力特性的研究具有重要的意义。本文利用模型试验和数值模拟方法，结合新疆某水电站深孔和表孔泄洪洞，对泄水建筑物水力特性进行研究，提出通过增加掺气设施以达到减蚀的目的，并优化掺气设施体型。从水力特性和掺气特性两个方面，论证了最优方案的合理性。主要研究内容包含以下方面：（1）利用大比尺水工模型进行不同工况下的泄洪洞过流试验，确定深孔泄洪洞渥奇段和反弧段空化数较小极易发生空化空蚀破坏，需要通过修改泄洪洞体型或者增加掺气设施加以优化；表孔溢洪洞斜坡段掺气坎后底空腔回水较为严重，需要对掺气设施的体型和尺寸进行优化。（2）采用RNG k-ε模型模拟紊流，利用VOF法追踪自由水面，对设置掺气设施前后共三种方案的深孔龙抬头段泄洪洞进行数值模拟，将数值计算与模型试验所得数据进行对比分析，证明数值方法的可靠合理性；并对掺气设施体型比较，认为侧向折流器加跌坎方案更优，，能够产生稳定、足够长的底空腔长度保护下游。（3）对掺气水流进行研究，采用前人试验研究成果对本文的掺气模型进行验证。然后再利用该掺气模型对深孔龙抬头段设置掺气设施的两种方案进行具体掺气效果的对比分析，以及对表孔泄洪洞斜坡段上掺气坎选型进行研究。（4）在表孔泄洪洞斜坡段掺气坎选型中，提出挑坎加折流坎组合、凸型差动挑坎加折流坎组合以及凸型差动挑坎加组合折流坎三种类型掺气方案。根据模型试验和数值计算，对各方案掺气坎后底空腔形态、下游水翅情况、近底掺气浓度沿程分布以及断面浓度垂线分布进行对比分析，最终确定最优方案。
[Abstract]:Flood discharge tunnel is one of the common drainage structures in water conservancy and hydropower projects. There have been a lot of cases at home and abroad which caused the destruction of the drainage structure due to improper design of the flood discharge tunnel, so the study of hydraulic characteristics of the flood discharge tunnel is of great significance. In this paper, the hydraulic characteristics of drainage structures are studied by using model test and numerical simulation method, combined with deep hole and surface hole flood discharge tunnel of a hydropower station in Xinjiang. It is put forward that the purpose of corrosion reduction can be achieved by adding aeration facilities and the shape of aeration facilities can be optimized. The rationality of the optimal scheme is demonstrated from two aspects: hydraulic characteristics and aeration characteristics. The main contents of the study are as follows: 1) the large scale hydraulic model is used to carry out the overflow test of the flood discharge tunnel under different working conditions, and the cavitation number of the deep hole flood discharge tunnel is determined to be small and the cavitation erosion is easy to occur in the reverse arc section. It needs to be optimized by modifying the shape of flood discharge tunnel or increasing aeration facilities, and the backwater of bottom cavity after aeration is more serious in slope section of surface hole overflow tunnel, so the shape and size of aeration equipment should be optimized. (2) RNG k- 蔚 model is used to simulate turbulent flow, and VOF method is used to track free water surface. Numerical simulation is carried out for the deep hole dragon flood discharge tunnel with three schemes before and after the installation of aeration facilities, and the data obtained from the numerical calculation and model test are compared and analyzed. It is proved that the numerical method is reliable and reasonable, and compared with the aeration device, it is considered that the lateral deflector with drop bar scheme is better, which can produce a stable and long enough bottom cavity length to protect the downstream. 3) the aeration flow is studied, and the aeration model is verified by the previous experimental results. Then the aeration model is used to compare and analyze the aeration effect of the two schemes with aeration facilities in the rising section of the deep-hole dragon, and the type selection of the aeration sill on the slope of the surface hole flood discharge tunnel is studied. 4) three kinds of aeration schemes are put forward in the selection of aeration ridges in the slope section of the surface hole flood discharge tunnel, such as the combination of the uplift kanga baffle, the convex differential pick-up and the convexity differential pick-up and the combined baffle. According to the model test and numerical calculation, the shape of bottom cavity, the downstream water wing, the distribution of near-bottom aeration concentration along the path and the vertical distribution of cross-section concentration of each scheme are compared and analyzed, and the optimal scheme is finally determined.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV135.2;TV131.6

【参考文献】