河床式水电站河道瞬变流及控制研究

发布时间：2018-03-27 16:55

本文选题：涌波　切入点：瞬变流　出处：《武汉大学》2017年硕士论文

【摘要】：河床式水电站一般修建在河道中下游,有水头低、引用流量大的特点。由于河床式水电站的水头低,当机组引用流量发生变化时,涌波占机组水头比重大,会对电站机组的安全稳定运行产生不良影响。对于布置于多江汊上的水利枢纽,多江之间的涌波往复现象明显,引起机组出力波动,引航道水位波动等问题。这直接关系到电网、船闸和库区安全的综合社会效益。所以分析涌波影响因素及传播规律,评价涌波对机组运行和航运的不良影响,探求涌波的有效控制措施具有研究意义。本文应用Delft3D软件对河床式水电站中涌波的影响因素、传播规律及其控制措施进行了较为系统的研究。主要内容如下:1.阐述涌波问题研究背景和意义,对明渠非恒定流、水电站涌波、涌波控制措施研究现状进行了概述,提出本文研究方法和内容。2.阐述浅水动力学基本理论,包括平面二维流动基本方程,浅水方程离散方法。介绍Delft3D软件的控制方程和时间差分方法。通过典型算例验证,模拟驼峰流和水电站尾水明渠非恒定流,与理论、文献结果对比,验证了 Delft3D模拟涌波的准确性,可见该软件可用于研究河道涌波问题。3.利用简单矩形河道模型研究机组流量变化值、导叶关闭时间、河床糙率、河道宽度及河道初始水深等因素对涌波的影响规律,以判别涌波的主要影响因素,作为涌波控制措施设计的依据。4.利用一岛两江河道模型分析机组不同运行方式与涌波的相互影响,选择合理的机组运行方案。模拟对比机组"甩负荷时与邻近闸门联合操作"和"导叶分段关闭"两种涌波控制措施的效果,选择效果较好的措施应用于实际工程模拟。5.结合某水利枢纽工程,研究多江汊上水电站涌波性态,分析涌波对河床式水电站运行机组和航运的影响。以最不利工况为例,分析"甩负荷时与邻近闸门联合操作"这一涌波控制措施的效果。本文运用CFD软件Delft3D,对河床式水电站过渡过程涌波现象进行了较系统的研究,得到了涌波影响因素及传播规律,涌波对库区流态、通航条件的影响。本文的研究成果可为河床式水电站设计提供参考。
[Abstract]:River bed type hydropower stations are generally built in the middle and lower reaches of the river, with the characteristics of low water head and large quoted flow. Because of the low water head of river bed type hydropower stations, the surge wave accounts for a large proportion of the unit water head when the unit suction flow changes. It will have an adverse effect on the safe and stable operation of the power station units. For the water conservancy projects arranged on the Duojiang branch, the reciprocating phenomenon between the multi-rivers is obvious, which causes the generating force fluctuation of the generating units. The fluctuation of water level in approach channel is directly related to the comprehensive social benefit of the safety of power grid, lock and reservoir area. Therefore, the influence factors and propagation rules of surge wave are analyzed, and the adverse effects of surge wave on unit operation and shipping are evaluated. It is of great significance to explore the effective control measures of surge. In this paper, Delft3D software is applied to the influencing factors of surge in river bed hydropower stations. The propagation law and its control measures are systematically studied. The main contents are as follows: 1. The background and significance of the research on the problem of surge are expounded, and the current situation of the research on the unsteady flow of open channel, the surge of hydropower station and the control measures of surge is summarized. The basic theory of shallow water dynamics, including the basic equations of planar two-dimensional flow and the discrete method of shallow water equations, is presented. The control equation and time difference method of Delft3D software are introduced. The simulation of hump flow and unsteady flow in the open tail channel of hydropower station is compared with the theoretical and literature results, and the accuracy of Delft3D simulation of surge is verified. It can be seen that the software can be used to study the problems of channel surge. 3. Using simple rectangular channel model to study the influence law of unit discharge value, lead blade closing time, river bed roughness, channel width and initial water depth, etc. In order to distinguish the main influencing factors of surge, as the basis of the design of surge control measures, the paper analyzes the interaction between unit operation mode and surge by using the model of one island and two rivers. Select reasonable operation plan of the unit, simulate and compare the effect of two kinds of surge control measures: "combined operation with adjacent gate" and "guide vane segment closure" when the unit is under load rejection, The measures with good effect are applied to the practical engineering simulation. 5. Combined with a water conservancy project, the surge behavior of the hydropower station at the Duojiang branch is studied, and the influence of the surge on the operating unit and shipping of the riverbed hydropower station is analyzed. Taking the most unfavorable working conditions as an example, This paper analyzes the effect of "combined operation of load rejection and adjacent gate" as a surge control measure. In this paper, CFD software Delft3D is used to study the phenomenon of surge in the transient process of river bed hydropower station, and the influencing factors and propagation law of surge are obtained. The influence of surge on the flow state and navigation conditions of reservoir area. The research results in this paper can be used as a reference for the design of river bed hydropower stations.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV737;TV139.2

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