叶顶间隙对诱导轮内部流动和空化特性的影响

发布时间：2018-01-19 21:37

本文关键词： 诱导轮叶顶间隙空化内部流动实验　出处：《浙江理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：诱导轮为轴流式叶轮,工作时为避免管壁与叶片之间发生摩擦或者碰撞,管壁和叶片之间存在一定大小的间隙,即叶顶间隙。诱导轮内部分流体受到叶片吸力面和压力面压差影响,在叶顶产生间隙泄漏流,这将对诱导轮的水力性能、内部主流流动及空化性能产生较大的影响。国内外对于诱导轮在不同叶顶间隙下的叶顶间隙涡的演化、空化泡分布的位置等内部流动细节缺少深入的研究。因此本文以一圆柱形等螺距诱导轮为研究对象,分析了不同叶顶间隙对诱导轮内部流动和空化性能的影响。首先对比分析了七种叶顶间隙下诱导轮水力性能的变化规律,并重点分析了三种典型叶顶间隙下的诱导轮内部流场、不同时刻内部流场的演化过程以及空化泡位置的分布。本文的主要研究工作如下:(1)采用UG三维软件对诱导轮进行三维建模,采用ICEM对诱导轮内部流道进行网格划分,并通过网格无关性验证,确定合理的网格数进行后续的数值计算。(2)非空化工况下,对三种叶顶间隙下诱导轮内部流场进行定常和非定常数值模拟。对比分析流量和叶顶间隙对诱导轮性能和内部流动的影响,及诱导轮内部流动随时间的演化过程。(3)对诱导轮进行外特性实验,获得扬程-流量的外特性曲线,并与数值计算结果进行对比分析,验证数值方法的准确性。(4)对诱导轮进行空化数值模拟,对比分析流量、叶顶间隙和空化数对内部空化流动、空化泡的发展和分布、叶片及弯管处压力分布及内部压力演变过程的影响。
[Abstract]:The induction wheel is an axial flow impeller, in order to avoid friction or collision between the tube wall and the blade, there is a certain gap between the tube wall and the blade. That is, the tip clearance. Some fluids in the inducer are affected by the pressure difference between the suction surface and the pressure surface of the blade, and a gap leakage flow is produced at the top of the blade, which will affect the hydraulic performance of the inducer. The internal mainstream flow and cavitation performance have a great impact on the evolution of the tip clearance vortices of the inducer wheel under different top clearance at home and abroad. The location of cavitation bubble distribution and other internal flow details are lack of in-depth study, so this paper takes a cylindrical equal pitch induction wheel as the research object. The influence of different tip clearance on the flow and cavitation performance of the inducer is analyzed. Firstly, the hydraulic performance of the inducer under seven kinds of tip clearance is compared and analyzed. The internal flow field of three typical tip clearance inducers is analyzed. The evolution process of internal flow field and the distribution of cavitation bubble position at different time. The main research work of this paper is as follows: 1) using UG 3D software to model the induction wheel. The ICEM is used to mesh the inner channel of the induction wheel, and through the mesh independence verification, the reasonable number of meshes is determined to carry on the subsequent numerical calculation under the condition of non-cavitation. The steady and unsteady numerical simulation of the flow field in the inducer under three kinds of tip clearance was carried out, and the effects of flow rate and tip clearance on the performance and internal flow of the inducer were compared and analyzed. And the evolution process of the induced wheel flow with time. 3) the external characteristic curve of the induced wheel is obtained and compared with the results of numerical calculation. The accuracy of the numerical method is verified. (4) the cavitation simulation of the inducer is carried out, and the flow rate, the tip clearance and the cavitation number are compared to analyze the cavitation flow, the development and distribution of cavitation bubble. Influence of pressure distribution and internal pressure evolution at blade and bend.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH31

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