斜向式导水机构内部流动的研究

发布时间：2018-04-04 02:58

本文选题：高水头贯流　切入点：斜向式导水机构　出处：《西华大学》2014年硕士论文

【摘要】：纵观我国水利水电事业的开发情况，运用于中低水头段的贯流式机组现在仍有相当大的发展空间。本课题主要研究应用于贯流式水轮机以及高水头贯流式水轮机的斜向式导水机构二重叶栅内部流动规律，从而为斜向式导水机构导叶设计理论及方法提供理论基础。由于这种贯流式水轮机不再设置蜗壳部件，随着实际的运行水头的提高，转轮进口所需的环量增大，全部环量只能通过斜向式导水机构来形成，必导致活动导叶负荷过重、扭曲严重，产生严重的脱流以及空蚀。同时，由于活动导叶锥形布置，严重扭曲的翼型必然导致其难以封水以及加工制造。因此，解决活动导叶和固定导叶各自应当形成多少环量的问题，对机组的设计、制造以及稳定运行至关重要。本课题的研究基于流体力学、水力机械流动理论，探究高水头贯流式水轮机流道内的水流运动规律，建立流动的理论模型，，得出斜向式导水机构二重叶栅流动轴面流速遵循Vm R=const的理论模型，并由自由涡理论，水流在二重叶栅中同样遵循Vu r=const理论，由此得出Vm R=const及Vu r=const的流动理论，并采用标准的k—模型完成斜向式导水机构二重叶栅内流场的CFD分析。并研究了同一工况下二重叶栅的最佳位置关系和两者之间环量分配情况，探寻二重叶栅环量分布关系对水轮机全流场性能的变化规律，以及对整个机组性能的影响，最终得到固定导叶、活动导叶二重叶栅的最佳位置关系和环量分布规律，为斜向式导水机构二重叶栅的水力设计提供理论依据。
[Abstract]:According to the development of water conservancy and hydropower industry in China, there is still considerable room for development of tubular units in middle and low head sections.This paper mainly studies the internal flow law of double cascade of inclined guide mechanism used in tubular turbine and high head tubular turbine, which provides a theoretical basis for the design theory and method of guide vane of inclined water guide mechanism.Since this type of tubular turbine is no longer equipped with volute parts, with the increase of the actual running water head, the amount of ring required for the inlet of the runner increases, and the total ring quantity can only be formed by the oblique water guide mechanism, which will lead to the excessive load of the active guide vane.The distortion is severe, resulting in severe decurrent and cavitation erosion.At the same time, because of the conical arrangement of the movable guide vane, the seriously twisted airfoil will make it difficult to seal water and manufacture.Therefore, it is very important for the design, manufacture and steady operation of the unit to solve the problem of how many rings should be formed each of the active guide vane and the fixed guide vane.Based on hydrodynamics and hydraulic mechanical flow theory, the research of this topic is to explore the flow movement law in the passage of high head tubular turbine, and to establish the theoretical model of flow.It is concluded that the axial flow velocity of double cascade of oblique diversion mechanism follows the theoretical model of VM R=const, and from the theory of free vortex, the flow of water follows the theory of Vu r=const in the double cascade, and the flow theory of VM R=const and Vu r=const is obtained.The standard k- model is used to analyze the flow field in the double cascade of oblique water conduction mechanism by CFD.The optimal position relation of double cascade and the distribution of ring quantity between them under the same working condition are studied, and the variation law of the distribution of double cascade ring on the whole flow field performance of hydraulic turbine and the effect on the performance of the whole unit are explored.Finally, the optimal position relation and distribution law of the double cascade with fixed guide vane and movable guide vane are obtained, which provides the theoretical basis for the hydraulic design of the double cascade of the oblique guiding mechanism.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV734.1

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