含沙水中长短叶片水轮机内部流动的数值模拟
发布时间：2018-11-26 19:05
【摘要】：迄今为止,关于含沙河流中运行的水轮机泥沙磨损破坏机理的研究取得了很大的进步,但还不十分成熟。 常规混流式水轮机在含沙河流运行过程中,水轮机的空蚀和磨损破坏非常严重,特别是在高水头状态下运行,情况更为严重,水轮机的空蚀和磨损破坏已是水电站安全运行的一个重要问题。事实证明,长短叶片混流式水轮机能够减轻空蚀破坏及泥沙磨损,但问题并没有得到彻底解决,故需要对长短叶片混流式水轮机内部固液两相流动进行研究,探讨水轮机内部沙水流场的流动机理,为长短叶片水轮机设计提供参考。 本文将其水轮机各过流部件作为整体来考虑,基于N-S方程,分别对其水轮机内的清水及沙水流动进行数值计算。研究的成果如下: 一、根据一具体水轮机的水力设计技术参数,采用Unigraphics软件分别对水轮机引水部件、导水机构、转轮及尾水管进行三维几何建模。并将建好的各过流部件三维模型导入Gambit软件中,并对其依次进行网格划分及指定边界类型和区域类型; 二、分别对清水中大流量工况、最优工况、小流量工况下水轮机内部流动进行数值计算; 三、分别对沙水中的颗粒体积浓度和直径一定流量不同,颗粒体积浓度和流量一定颗粒直径不同,颗粒直径和流量一定颗粒体积浓度不同的情况下水轮机内部流动进行数值计算;通过对清水和沙水的数值计算结果的对比分析,获得了长短叶片水轮机各过流部件的泥沙磨损和空蚀破坏规律。计算结果与实际电站在运行过程中发生的情况基本吻合。
[Abstract]:So far, great progress has been made in the study of sediment wear failure mechanism of turbine running in a sandy river, but it is not very mature. The cavitation erosion and wear damage of conventional Francis turbine is very serious during the operation of the sand bearing river, especially in the high head condition, the situation is more serious. Cavitation erosion and wear and tear of hydraulic turbines have become an important problem in the safe operation of hydropower stations. It has been proved that long and short vane Francis turbine can reduce cavitation erosion and sediment wear, but the problem has not been completely solved, so it is necessary to study the solid-liquid two-phase flow in the long and short blade Francis turbine. The flow mechanism of sand flow field in turbine is discussed, which provides a reference for the design of long and short blade turbine. Based on N-S equation, the flow of clean water and sand water in the turbine is numerically calculated by considering the flow components of the turbine as a whole. The results are as follows: firstly, according to the hydraulic design technical parameters of a specific hydraulic turbine, Unigraphics software is used to model the three dimensional geometry of the turbine diversion unit, water guide mechanism, runner and draft tube respectively. The 3D model of the constructed flow components is imported into the Gambit software, and it is meshed in turn, and the boundary type and the area type are specified. Secondly, the internal flow of the turbine is numerically calculated under the conditions of large flow rate, optimal working condition and small flow rate. Third, the particle volume concentration and diameter of sand water are different, and the particle volume concentration and flow rate are different. When the particle diameter and flow rate are different, the flow inside the turbine is numerically calculated. By comparing and analyzing the numerical results of clear water and sand water, the rules of sediment wear and cavitation erosion of each flow part of long and short blade turbine are obtained. The calculated results are in good agreement with the actual operation of the power station.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311
本文编号：2359364
[Abstract]:So far, great progress has been made in the study of sediment wear failure mechanism of turbine running in a sandy river, but it is not very mature. The cavitation erosion and wear damage of conventional Francis turbine is very serious during the operation of the sand bearing river, especially in the high head condition, the situation is more serious. Cavitation erosion and wear and tear of hydraulic turbines have become an important problem in the safe operation of hydropower stations. It has been proved that long and short vane Francis turbine can reduce cavitation erosion and sediment wear, but the problem has not been completely solved, so it is necessary to study the solid-liquid two-phase flow in the long and short blade Francis turbine. The flow mechanism of sand flow field in turbine is discussed, which provides a reference for the design of long and short blade turbine. Based on N-S equation, the flow of clean water and sand water in the turbine is numerically calculated by considering the flow components of the turbine as a whole. The results are as follows: firstly, according to the hydraulic design technical parameters of a specific hydraulic turbine, Unigraphics software is used to model the three dimensional geometry of the turbine diversion unit, water guide mechanism, runner and draft tube respectively. The 3D model of the constructed flow components is imported into the Gambit software, and it is meshed in turn, and the boundary type and the area type are specified. Secondly, the internal flow of the turbine is numerically calculated under the conditions of large flow rate, optimal working condition and small flow rate. Third, the particle volume concentration and diameter of sand water are different, and the particle volume concentration and flow rate are different. When the particle diameter and flow rate are different, the flow inside the turbine is numerically calculated. By comparing and analyzing the numerical results of clear water and sand water, the rules of sediment wear and cavitation erosion of each flow part of long and short blade turbine are obtained. The calculated results are in good agreement with the actual operation of the power station.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311
【引证文献】
相关硕士学位论文 前1条
1 刘争光;长短叶片混流式水轮机内部固液两相流动数值模拟[D];西华大学;2012年
，本文编号：2359364
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