基于数值方法的长短叶片混流式水轮机性能研究

发布时间：2019-04-27 05:20

【摘要】：研究发现,长短叶片混流式水轮机在提高高水头水轮机工作性能方面具有明显优势,为了更广泛地推广应用这种新型水轮机有必要对其进行更全面深入的研究,本文以某型长短叶片水轮机为研究对象,采用数值模拟技术对其不同运行工况进行了全流道计算,并根据计算结果分析了该水轮机的能量特性、空化特性和力学特性。主要研究内容有:(1)利用SolidWorks,bladegen等软件建立了水轮机全流道三维模型,利用icem,turbogrid等软件进行了网格划分,将网格模型导入cfx进行参数设置并计算。(2)分析了水轮机典型工况下各过流部件的流场压力分布和流速分布情况,能量损失情况,发现中流量工况下流态最好,水力损失最小,能量特性最好,其它工况能量特性较差。对比了长短叶片转轮和常规叶片(仅长叶片)转轮的内部流动情况和压力分布情况,发现两种水轮机能量特性相近。(3)分析了该型水轮机转轮的翼型压力分布和水流流动状态,发现小流量工况下叶片头部易发生空化,中流量工况和大流量工况下叶片出口更易发生空化。与常规转轮进行了对比,发现长短叶片转轮空化性能优于常规(仅长叶片)转轮,这对以后提高转轮空化性能的改型研究有一定帮助。根据尾水管内的涡带产生情况预测了尾水管内的空化,在小流量工况和大流量工况更容易发生空腔空化,中流量工况下不易发生空腔空化。(4)采用双向流固耦合的方法计算分析了各个工况下水轮机转轮的应力和应变分布情况,几种工况下转轮的最大应力处均出现在转轮叶片的出水边与上冠衔接处。
[Abstract]:It is found that the Francis turbine with short and short blades has obvious advantages in improving the working performance of the turbine with high head. In order to popularize and apply this new type of turbine more extensively, it is necessary to carry out a more comprehensive and in-depth study on it. In this paper, a hydraulic turbine with short and short blades is taken as the object of study, and the full passage calculation of the turbine under different operating conditions is carried out by using numerical simulation technology. The energy characteristics, cavitation characteristics and mechanical characteristics of the turbine are analyzed according to the calculated results. The main research contents are as follows: (1) the three-dimensional model of hydraulic turbine runner is established by using SolidWorks,bladegen and other softwares, and the grid is divided by icem,turbogrid and other software. The grid model is imported into cfx and the parameters are set and calculated. (2) the pressure distribution and velocity distribution of the flow field and the energy loss are analyzed under the typical working conditions of the turbine. It is found that the flow pattern is the best under the middle flow condition. The hydraulic loss is the smallest, the energy characteristic is the best, and the other conditions are poor. The internal flow and pressure distribution of the runner with short and short blades are compared with those with conventional blades (only long blades). It is found that the energy characteristics of the two kinds of turbines are similar. (3) the pressure distribution of the airfoil and the flow state of the runner are analyzed, and it is found that cavitation occurs easily in the blade head under the condition of small flow. Cavitation occurs more easily at the vane outlet under medium flow condition and large flow condition. Compared with the conventional runner, it is found that the cavitation performance of the runner with short and short blades is better than that with the conventional runner (only long blade), which is helpful to the study of the improvement of the cavitation performance of the runner in the future. According to the vortex band in the draft tube, the cavitation in the draft pipe is predicted, which makes it easier to cavitation in the small flow and large flow conditions. Cavity cavitation is not easy to occur under medium flow condition. (4) the stress and strain distribution of hydraulic turbine runner under various working conditions are calculated and analyzed by two-way fluid-solid coupling method. The maximum stress of the runner appears at the outlet edge of the runner blade and the joint of the crown under several working conditions.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TK733.1

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