小湾河水库台阶溢洪道泄流三维数值模拟

发布时间：2019-03-20 18:06

【摘要】：台阶溢洪道是集泄流和消能设施于一体的消能工，消能效果良好且工程造价低。随着碾压混凝土技术的发展，台阶溢洪道得到广泛应用，因此，对台阶溢洪道水力特性的研究具有重要的实际意义。对台阶溢洪道水力特性的研究，通常借助物理模型试验和数值模拟方法。近些年来，随着计算机性能的不断提升和计算流体力学的快速发展，使得数值模拟技术已成为研究台阶溢洪道水力特性的重要手段。本文主要通过数值模拟方法对台阶溢洪道的水力特性进行了研究，主要研究成果如下：在CAD中建立三维模型，导入ICEM中划分非结构网格，利用FLUENT软件，选用k－ε两方程紊流模型和VOF方法，对小湾河台阶溢洪道按定常流进行了三维数值模拟，将数值模拟结果与模型试验结果对比发现，两者吻合良好。小湾河台阶溢洪道上的水流为滑行水流。台阶上产生顺时针漩涡，水流速度由漩涡中心的零向四周逐渐增大。台阶上紊动耗散率和紊动能的分布规律基本一致，以台阶凹角处为中心，，向四周逐渐变大，但前者在凸角上达到最大，后者在台阶凸角两侧最大。台阶竖直面的上部均存在负压区，随着台阶的下移，负压区的范围越来越小。台阶底部压力最大，沿着竖直面向上，压力逐渐减小至负压，然后又增大。台阶水平面上基本为正压，但在台阶凸角处可能会出现较小的负压。从台阶凹角处沿着水平面，压力分布规律为：先减小，后增大，达到最大值后急剧减小，甚至出现负压。并在首部台阶通过掺气的方式来缓解台阶上负压的产生。
[Abstract]:Step spillway is a kind of energy dissipator with discharge and energy dissipation facilities, which has good energy dissipation effect and low engineering cost. With the development of roller compacted concrete (RCC) technology, stepped spillway has been widely used. Therefore, the study on hydraulic characteristics of stepped spillway is of great practical significance. The hydraulic characteristics of step spillway are usually studied by physical model test and numerical simulation. In recent years, with the continuous improvement of computer performance and the rapid development of computational fluid dynamics, numerical simulation technology has become an important means to study the hydraulic characteristics of stepped spillway. In this paper, the hydraulic characteristics of step spillway are studied by numerical simulation method. The main results are as follows: three-dimensional model is built in CAD, unstructured grid is introduced into ICEM, and FLUENT software is used. The k-蔚 two-equation turbulence model and VOF method are used to simulate the steady flow in the stepped spillway of Xiaowanhe River. The comparison between the numerical simulation results and the model test results shows that the two models are in good agreement with each other. The stream on the stepped spillway of Xiaowan River is a sliding flow. A clockwise vortex is generated on the steps, and the velocity of the flow increases gradually from zero in the center of the vortex. The distribution law of turbulent dissipation rate and turbulent energy on the step is basically the same. At the center of the step concave angle, the turbulent dissipation rate increases gradually, but the former reaches the maximum on the convex angle, while the latter reaches the maximum on the two sides of the convex angle of the step. There is a negative pressure zone in the upper part of the vertical face of the steps, and the range of the negative pressure zone becomes smaller and smaller with the downward movement of the steps. The pressure at the bottom of the step decreases gradually to negative pressure and then increases. The horizontal level of the step is basically positive, but there may be a small negative pressure at the convex angle of the step. From the angle of the step along the horizontal plane, the pressure distribution law is as follows: first decrease, then increase, reach the maximum value, then sharply decrease, and even appear negative pressure. And in the first step through aeration to alleviate the negative pressure on the step.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV651.1;TV135.2

【参考文献】