不同体型台阶式溢洪道水力特性研究

发布时间：2018-03-18 00:10

本文选题：台阶式溢洪道　切入点：水力特性　出处：《青海大学》2017年硕士论文　论文类型：学位论文

【摘要】：泄水建筑物在水利工程中具有至关重要的地位,起着宣泄水库水流和保证水利工程安全的作用。台阶式溢洪道作为泄水建筑物中新型消能工,它具有缩减工期、消能率高等优点,但其坝面水流流态较为复杂,且与大气相接触,水流中掺入大量气体,产生水气两相流。水流产生的掺气、空蚀、脉动等现象会对溢洪道产生重大影响,甚至危害泄水建筑物的安全。本文结合青藏高原某水库台阶式溢洪道,运用水工物理模型与数值模拟两种手段对其水力学问题作了研究。物理模型试验共设计了四种体型,观测了不同流量时水流的流态、压强特性和消能特性等;通过FLUENT软件针对一种台阶体型对溢洪道作数值计算。主要研究成果:台阶溢流坝面上的水流流态大致划分成滑行水流、过渡水流和跌落水流;研究分析了不同台阶式溢洪道体型水面线和流速的分布规律;通过测量各台阶测点时均压强和脉动压强以及分析其数据可知,水平面上的时均压强沿台阶凹角向外缘方向先有所降低,随后慢慢增加,台阶竖直面时均压强会形成负压区,台阶水平面上的脉动压强在凸角处最大,台阶各测点时均压强和脉动压强强度沿程均呈波浪式发展;同时对不同台阶体型下沿程消能率的分布情况以及影响因素作了研究,并分析了其消能机理;数值模拟方法在台阶式溢洪道计算上是安全可靠的,能够快速详细的获得其水力参数。
[Abstract]:As a new type of energy dissipator in the water discharge structure, the stepped spillway is a new type of energy dissipator, which has the function of reducing the duration of the project, because it plays an important role in water conservancy engineering, and plays an important role in discharging the reservoir water and ensuring the safety of the water conservancy project. The energy dissipation rate is high, but the water flow pattern on the dam surface is more complicated, and it is in contact with the atmosphere, and a large amount of gas is mixed in the water flow, which produces a two-phase flow of water and gas. The phenomena of aeration, cavitation erosion and pulsation produced by the water flow will have a significant impact on the spillway. In this paper, hydrophysical model and numerical simulation are used to study the hydraulic problems of a stepped spillway of a reservoir on the Qinghai-Tibet Plateau. The flow state, pressure characteristics and energy dissipation characteristics of the flow are observed at different flow rates, and the spillway is numerically calculated by FLUENT software for a kind of step shape. The main research results are as follows: the flow pattern on the stepped spillway surface is roughly divided into sliding flow. The distribution law of surface line and velocity of different stepped spillways are studied and analyzed. By measuring the average pressure and pulsating pressure of every step measuring point and analyzing the data, it is known that, The time average pressure on the horizontal plane decreases at first along the concave angle of the step to the outer edge, and then increases slowly. The average pressure on the vertical plane of the step will form a negative pressure zone, and the pulsating pressure on the horizontal plane of the step is the largest at the convex angle. The average pressure and pulsating pressure intensity along the steps are all wave-like, and the distribution of the energy dissipation rate along the different steps and the influencing factors are studied, and the energy dissipation mechanism is analyzed. The numerical simulation method is safe and reliable in the calculation of stepped spillway, and the hydraulic parameters can be obtained quickly and in detail.
【学位授予单位】：青海大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV135.2

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