【作者】 李书芳；

【导师】 杨纪伟；

【作者基本信息】 河北工程大学 ， 水力学及河流动力学， 2007， 硕士

【摘要】 泄洪消能及伴随着的泄洪雾化问题是保证高水头电站安全运行的重要问题。泄洪所形成的雾化降雨对电站厂房、电器设备、交通公路及水利工程附近居民生活等都有很大的影响。而雾流扩散的主要影响因素是越坝气流(包括水舌风)运动特性,雾化影响最严重的区域发生在坝后分离漩涡区。因此,研究越坝气流运动发展形态,准确预测坝后绕流分离漩涡区的范围,对水电站的安全运行有重要意义。本文是基于国家自然科学基金资助重点项目《雅砻江水电开发联合研究》(50539060)中的雾流降雨范围部分的研究。本文主要内容为:首先对越坝气流、雾化降雨、后台阶流的相关情况及基础理论做了简单介绍,然后讲述了物理模型试验和数值模拟研究过程及得到的结论:物理模型试验在环境风洞中进行,以1999年水科院对二滩水电站进行原型观测数据为依据制作模型,试验所得表孔和中孔全开模型回流区纵向长度分别在6.53～7.6和5.87～6.8倍坝高度之间,可见泄流方式对越坝气流有一定影响;雾流降雨范围试验与原型观测结果基本相似,初步表明通过采用人工生成水雾形成雾源,在风洞中进行雾流降雨范围和越坝气流的模拟是可行的;数值模拟基于FLUENT流体工程软件进行,采用与物理试验相同的几何模型及工况,使用Realizableк-ε湍流模型对越坝气流进行了数值模拟,数值模拟结果较物理模拟结果略偏大,总的来说两种模拟结果符合较好,表明用该方法研究越坝气流运动是基本可行的。并使用该湍流模型对不同范围Re下的越坝气流进行研究,分析坝后回流区的纵向长度、涡心位置随Re数的变化以及水舌存在对越坝气流回流区的影响。此外,鉴于越坝气流运动发展形式同后阶流运动发展形式的某些相似之处,本文对越坝气流和后阶流进行了对比和分析。更多还原

【Abstract】 In the modern hydraulic engineering construction, baffle of the rapid flood and the atomization following it is the most important problem in a high-head power station and ensure it safety in operation. The atomized rain formed by rapid flood has a big impact on the power station. The principal factor influence the diffusion of atomized-flow is the over-dam-flow, and the serious zone of the atomized rain is in the vortex zone behind the dam, so, it is significant to study the motion of over-dam-flow and accurately predict the vortex zone.This paper bases on nationality naturalness science fund item, research of area of the atomized rain. the fund number is 50539060. The primary coverage of this paper is: firstly, gave a brief descriptive on the over-dam-flow、atomized rain、backward-facing step and relating basic theory in the paper, then introduced the research procedure of the physical test and results: The physical test has done in wind tunnel, the test model was made based on dates of the prototype measurements of er-tan hydropower station, and the prototype measurement has done by the Institute of Hydraulic and Hydroelectrically of China in 1999. The test results indicate that the height hole model’s and the middle hole model’s regurgitation zone length is 6.53～7.6 and 5.87～6.8 fold of the dam height respectively, it seems that the draw mode has a impact on the over-dam-flow. This preliminarily indicates that it is feasible to study the atomized rain and over-dam-flow in wind tunnel; Numerical simulation was done based on FLUENT, use Realizableк-εturbulent model simulated the over-dam-flow in the same geometry model and work conditions as the physical test. The simulation results prove that also the result a few bigger then the physical test, the numerical result is consistent with the test, and the numerical simulation is feasible in model the over-dam-flow. At last, we studied the flow in different Reynolds number under the same numerical method, analyzed the variations of the regurgitation length and the vortex center based on the variation of the Reynolds number. At the same time, as the over-dam-flow is similar to the backward-facing step flow in some case, we also give a comparison on the two flows in this paper.更多还原