【作者】 马惠萍；

【导师】 齐学义；

【作者基本信息】 兰州理工大学 ， 流体机械及工程， 2009， 硕士

【摘要】 近些年来,越来越多的研究人员将计算流体动力学——CFD技术运用在流体机械内部流场分析与水力模型的研究和开发中。该方法已成为流体机械水力模型设计与开发的主流。CFD数值计算技术能较准确地获得流体机械内部流场分布及过流部件内部流动状态信息,为研究流体机械水力性能与稳定性提供理论基础,是成功设计出高性能的流体机械和对现有的流体机械进行优化改型的有效手段。对开发较低水头水能资源来说,在水轮机转轮的设计中,高比转速混流式水轮机转速高、体积小、效率高且高效区宽、结构紧凑等优势,是一种经济、适宜的水轮机型式。现阶段我国对水力资源的开发持续升温,技术成熟、经济可行的中小水电尤其受到青睐。为此,开发出性能优良的高比转速混流式水轮机水力模型,能更加合理、充分和有效地利用水力资源,把潜在的资源优势转化成经济效益和社会效益,意义十分重大。本课题的主要研究内容和所做的主要工作如下:1、参照水头段和比转速相近、性能优良的已有转轮水力模型全流道的几何参数,采用二元理论ω=0的方法,遵照转轮要满足在一定使用水头下,有尽可能高的转速和尽可能大的过流能力、较高的最高效率和平均效率,要有良好的空蚀性能、工作稳定性和对变工况的适应能力等的要求,设计出了HL300的翼型和叶栅及转轮的初始方案。2、对初始转轮方案进行精确的全流道三维实体造型和网格划分,这为提高过流部件内部流动CFD数值模拟精度及其性能预测的准确性奠定可靠的基础。3、CFD数值模拟,采用雷诺时均Navier-Stockes方程和RNGk-ε湍流模型,利用SIMPLEC算法对初始转轮设计方案进行模拟计算,并以模拟结果获得的流场信息为据,对初始转轮叶栅与翼型进行修型和调整,以及对其它过流部件进行适当修型或对某些参数进行相应地调整,直到满意为止确定最终方案,在其运行中的典型工况(大流量工况、最优工况和小流量工况)共25个计算工况点的运行状况进行了数值模拟,给出了HL300的转轮水力模型方案并绘制出木模图。本项课题研究工作中的主要创新点:1、提出了尾水管弯肘部分基于Pro/E的拆分组装设计的新方法,解决了常用方法中存在的建模不够精确及制造工艺性差等问题。2、通过本课题的研究得到一个适用于20m水头段的预测性能良好的新转轮水力模型方案。由于时间、条件和本人经验不足所限,本课题做的工作有限,有很多工作目前还没有进行到位。文中给出的水力模型方案,还有很大的提升空间,有待于以后继续深入研究和探讨。更多还原

【Abstract】 In recent years, more and more researchers use the computational fluid dynamics—CFD in the analysis of internal flow field of the fluid machine, as well as the study and development of the waterpower model. This way has been the artery in the study and development of the waterpower model. Numerical calculation technique of CFD can get the distributing of the internal flow field in the fluid machine and the information of the internal flow status in the flow-passing parts relatively accurate. This not only provide theoretical basis for the research of the performance and the stability of the fluid machine and the engineering hydraulic, and also is the efficiency measure of the designing high-powered fluid machine successfully and optimizing remodel of the existing fluid machine.For the development of low-head hydropower resources, In the design of turbine runner, High specific speed Francis turbine have the advantages of high-speed, small size, high efficiency and high-performance wide-area, compact structures, which is an economic and appropriate type of turbine. At the present, the development of China’s water resources sustained increasing, the middle-mall hydropower that the technology is economically feasible and technologically is very popular. So, the development of High specific speed Francis turbine model which have excellent performance can use the water resources more reasonably, sufficiently and effectively. And it can transform the advantages of the potential resource into the benefit of the economy and society, which have great significance.The main research and the major work done in this paper as follows:1. The geometric parameters are designed according to the flow channel of the hydraulic model that has similar head and specific speed, as well as the excellent performance. Using the dualistic Theoryω= 0 , In accordance with the request that runner have the highest speed and conveyance capacity, the higher maximum efficiency and average efficiency, the good cavitations performance, stability and the adaptability for changing work condition .etc. Initial scheme about the airfoil, cascade and the runner is designed for the HL300.2. Initial program of the runner is modeled three-dimensionally and mesh accurately. This lay the reliable basis for the precision of the CFD simulation and the accuracy of the performance prediction of the internal flow in the flow-passing.3. In this paper, the numerical simulation on the initial runner has been done by using Reynolds average N-S equation and RNG k-εturbulence model and SIMPLEC algorithm. In this numerical simulation, there are all 25 calculation points been selected on typical working conditions that are the big flow condition the optimal condition and small flow condition. With the simulation results to repair and adjust the cascade and aerofoil of initial blades, and other flow parts until satisfaction, finally design out the HL300 hydraulic model and draw the form drawing.Main innovations in this research work:1. Put forward the new method of split and assembling of the elbow of the draft tube base on Pro/E and solve the problem that occurred during the mechanical processing and modeling by the usual method and etc.2. A new hydraulic model with suitable prediction and good energy performance of the water head of 20m has been designed in this topic research.Due to the limits of time and conditions and my lack of experience, there are a lot of work not done well. Its doesn’ t satisfied that the Hydraulic model in this paper, and technical performance indicators are not enough advanced too. There has further room for further study.更多还原