混流式水轮机转轮内部流动的数值模拟及PIV测试探究

发布时间：2019-05-03 18:38

【摘要】：近年,我国水轮机设计制造水平大力提高,目前已步入世界先进水平行列。但水轮机水力设计水平与国际水平还有一定的差距,尤其是在转轮的能量特性和空化性能方面。混流式水轮机是目前应用最广泛的一种水轮机型式,开展混流式水轮机转轮内部涡流以及转轮内空化的研究对水轮机的水力优化设计具有较大的指导作用。本文以一混流式水轮机作为研究对象,建模完成后对其进行全流道数值模拟及试验分析。首先,对7个工况下的内部流动进行了数值模拟,主要研究叶道涡;再采用空化模型,研究转轮内部空化;同时,应用PIV测试技术对水轮机转轮叶道涡进行观测试验,尝试将该技术应用于转轮内流速测试,探索可行的测试途径。本研究具体内容如下:(1)基于所选的水轮机,建立三维几何模型,划分质量合格的网格。将各过流部件网格导入ANSYS中进行前处理,划定域、设定边界条件、交界面,以及计算精度。对水轮机的全流道进行数值模拟计算。(2)对大开度、小开度工况下进行了叶道涡数值模拟,分别对同开度、不同单位转速以及同单位转速、不同开度条件下转轮内部叶道涡进行了比较。(3)对大开度、小开度工况下进行了空化的数值模拟,分别对同开度、不同单位转速以及同单位转速、不同开度条件下转轮内部空化情况进行了比较。(4)在水轮机试验台上尝试搭建PIV测速装置,针对转轮内部流态进行测试,观测转轮内叶道涡,并通过图片数据处理,得出水轮机转轮内部水流的流线、速度矢量等数据。
[Abstract]:In recent years, the level of turbine design and manufacture in China has been greatly improved, and now it has entered the ranks of advanced level in the world. However, there is a certain gap between hydraulic design level of hydraulic turbine and international level, especially in the aspects of energy characteristics and cavitation performance of runner. Francis turbine is the most widely used type of water turbine at present. The research on internal eddy current and internal cavitation of Francis turbine runner is of great significance to the hydraulic optimization design of Francis turbine. In this paper, a Francis turbine is taken as the research object, and the full channel numerical simulation and experimental analysis are carried out after the modeling is completed. Firstly, the numerical simulation of internal flow under 7 conditions is carried out, mainly on the blade vortex, and then the cavitation model is used to study the internal cavitation of the runner. At the same time, the PIV testing technology is used to observe the vortex of the turbine runner and try to apply the technology to the velocity measurement of the runner, and explore the feasible way to test the flow velocity in the runner. The main contents of this study are as follows: (1) based on the selected hydraulic turbine, a three-dimensional geometric model is established and a qualified mesh is created. All over-flow component meshes are imported into ANSYS for pre-processing, delineation, setting of boundary conditions, interface, and calculation accuracy. The full passage of hydraulic turbine is numerically simulated and calculated. (2) the vortex numerical simulation is carried out under the conditions of large opening and small opening, respectively, for the same opening, different unit speed and the same unit speed, respectively, for the same opening degree, different unit speed, and the same unit speed, respectively. (3) numerical simulation of cavitation is carried out under the conditions of large opening and small opening, respectively, for the same opening, different unit speed and the same unit speed, respectively, for the same opening degree, different unit speed, and the same unit speed, respectively, under the conditions of large opening and small opening, the cavitation of the runner is simulated by numerical simulation under different opening conditions. The cavitation conditions of the runner under different opening conditions are compared. (4) the PIV velocity measuring device is set up on the hydraulic turbine test bench to test the internal flow pattern of the runner, observe the vortex inside the runner, and deal with the picture data through the processing of the picture data, and the internal cavitation of the runner is compared with that of the runner under different opening conditions. The flow line, velocity vector and other data of internal flow of hydraulic turbine runner are obtained.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK733.1

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