【作者】 朱国俊；

【导师】 罗兴錡； 郭鹏程；

【作者基本信息】 西安理工大学 ， 水利水电工程， 2009， 硕士

【摘要】 转轮是水轮机的核心部件,转轮设计的好坏直接关系到水轮机的效率、运行稳定性和空化性能。为了提高水轮机的总体性能,水轮机转轮的水力设计理论与方法一直是水力机械研究领域关注的热点。本文针对轴流式水轮机叶片的水力优化设计方法进行研究,综合Bezier曲线参数化技术,全三维粘性CFD计算方法和NSGA-Ⅱ遗传算法,发展了一种基于NSGA-Ⅱ的适用于轴流式转轮叶片的CAD-CFD联合的多目标水力优化设计方法。该方法以轴流式转轮叶片的形状参数为优化变量,以转轮的能量性能和空化性能为目标函数,将NSGA-Ⅱ遗传算法引入作为优化工具来实现叶片的多目标优化设计。这种多目标水力优化设计方法的优化过程全部由计算机仿真完成,提高了设计工作的效率。将ZZ440轴流式转轮叶片作为优化设计的对象,以Bezier曲线参数化技术为基础,采用了叶片进口边沿轴向变化、叶片进口边沿轴向和周向变化、叶片进出口边分别在轴向和周向同时变化的三种参数化方法对轴流式叶片进行了表达,然后分别将这三种方法表达的轴流式叶片与具有NSGA-Ⅱ算法的CAD-CFD联合优化方法相结合进行了轴流式叶片的多目标优化设计,并对三种参数化方法的优化结果进行比较,发现将叶片的进出口边位置都作为设计变量参加优化的参数化方法是相对来说最好的。接下来,采用本方法进行了某电站水轮机模型活动导叶的水力性能优化设计。优化后导叶流道的进出口总压损失减少了26.97%,并且导叶表面上的最低静压力值上升了34.176%。优化后的导叶不仅流动损失减少了,而且也具有了更好的空化性能。计算结果表明，对于轴流叶轮机械叶片的优化问题,本文提出的多目标水力优化设计方法能够以较少的变量控制叶片几何形状,且能有效分析各设计变量对目标函数的影响程度和范围,缩小优化问题的规模,得到满意的优化结果,可作为一种有效的轴流式转轮叶片优化设计工具。更多还原

【Abstract】 Runner is the core component of hydraulic turbine, and its quality of design directly affects the hydraulic turbine’s efficiency, operation stability and cavitation performance. In order to improve the total performance of hydraulic turbine, its hydraulic design theory and method has always been the focus of hydraulic machine region.Integrated parametric technology of Bezier curve,3D viscous flow CFD calculation and NSGA-II algorithm, a CAD-CFD joint optimization design method for Kaplan turbine runner was put forward. Shape parameters of hydraulic turbine blade were used as optimization variable, energy and cavitation performances were used as objective function, and the multi-objective optimization for Kaplan turbine was carried out. The whole optimization process is completed by computer, and the design efficiency was greatly improved.The ZZ440 runner blade was used as an optimal design object. Based on the parametric technology of Bezier curve, three kinds of parametric method was used to parameterized Kaplan blade. These three methods were the inlet edge changing along with axial direction and the inlet edge changing along with axial and circumferential direction, and the third one was the inlet and outlet edge changing along with axial and circumferential direction at the same time. The Kaplan blade multi-objective optimization was carried out. According to the optimization results, the parametric method which the inlet and outlet edge change along with axial and circumferential direction was the best.Then the guide vane optimization was carried out. And the results shown that the total pressure loss reduced 26.97%, and the minimal pressure in guide vane blade increased 34.176%. For the optimizated guide vane the loss not only was reduced, the cavitation performance but also was improved.For the multi-object optimization method proposed in this paper, lesser variables can not only be used to control the blade shape, the extent of influence of each variable on objective function but also be analyzed effectively to reduce the scale of optimization problem and get the satisfying results. So it is an effective optimization design tool for Kaplan turbine runner.更多还原