离心泵内流场三维湍流数值模拟与PIV测试研究

发布时间：2018-09-06 09:57

【摘要】：由于采用长短叶片相间设计的复合式叶轮能够避免叶片进口排挤、有效阻止涡流及脱流的产生和发展及改善叶轮流道的扩散状况,使其具有流量小、扬程高、高效、小流量稳定等性能指标,同时具有结构紧凑、维修方便等特点。目前,具有长短叶片的复合式叶轮已广泛应用于石化、轻工及航空航天等领域。不同的短叶片设置方案对离心泵性能有不同的影响,故有必要从离心叶轮内特性出发来研究分析短叶片不同设置方案对泵外特性的影响。本文采用三维湍流数值模拟方法对三种不同短叶片设置方案的叶轮内流场进行研究,同时利用粒子图像速度仪(PIV)测试了其中两副叶轮的内流场,分析得出了长短叶片离心叶轮内部流动参数的分布规律；本文最后在前人研究的基础上,设计了三副低比转速高速离心泵,利用ANSYS CFX软件计算了其全流道的三维定常湍流流动；研究结果对长短叶片离心叶轮的进一步优化设计有一定的参考价值。本文的主要工作有： 1、结合AutoCAD与Pro/ENGINEER软件对叶轮及蜗壳进行三维实体造型,采用ICEM-CFD软件对叶轮及蜗壳进行结构化网格剖分； 2、基于雷诺时均Navier-Stockes方程和标准k-ε双方程湍流模型,利用CFD软件(ANSYS CFX11.0)对三副长短叶片离心叶轮在七种不同流量工况进行全流道定常数值模拟,捕捉了叶轮内部相对速度、静压等重要流动参数的分布规律,并进行对比分析； 3、应用粒子图像速度仪(PIV)对2副长短叶片离心叶轮的同一个叶槽在五种流量工况下的内流场进行测试研究,分析得到了叶轮中间断面的相对速度矢量图和等值线图,并对比分析不同叶轮内部相对速度分布状况； 4、对比分析了数值模拟结果和PIV测试结果,分析了两者之间存在差异的原因； 5、介绍了低比转速高速离心泵的设计理论,设计了三副短叶片起始直径不同的复合叶轮及蜗壳,采用非结构化网格对高速离心泵进行整机网格剖分,数值模拟计算了五种流量工况下的内流场,对比分析了叶轮内部的静压场及相对速度场,分析了短叶片起始直径不同对内部流动的影响。
[Abstract]:Because the composite impeller with long and short blade interphase design can avoid the extrusion of blade inlet, prevent the generation and development of eddy current and deflow effectively and improve the diffusive condition of impeller runner, the impeller has small flow rate, high lift and high efficiency. Small flow stability and other performance indicators, with compact structure, easy maintenance and other characteristics. At present, composite impellers with long and short blades have been widely used in petrochemical, light industry, aerospace and other fields. Different short blade setting schemes have different effects on the performance of centrifugal pump, so it is necessary to study and analyze the influence of different short blade setting schemes on the external characteristics of centrifugal impeller from the point of view of the inner characteristics of centrifugal impeller. In this paper, three dimensional turbulence numerical simulation method is used to study the flow field in impeller with three different short blade schemes, and the inner flow field of two impellers is measured by particle image velocimeter (PIV). The distribution of flow parameters in long and short blade centrifugal impellers is obtained. Finally, three pairs of low specific speed and high speed centrifugal pumps are designed on the basis of previous studies, and the three-dimensional steady turbulent flow in the whole flow channel is calculated by ANSYS CFX software. The results have some reference value for the further optimization design of the centrifugal impeller with long and short blades. The main work of this paper is as follows: 1. Using AutoCAD and Pro/ENGINEER software to model the impeller and volute, using ICEM-CFD software to mesh the impeller and volute. 2. Based on the Reynolds time averaged Navier-Stockes equation and the standard k- 蔚 two-equation turbulence model, the three-pair long and short blade centrifugal impellers are numerically simulated in seven different flow conditions using CFD software (ANSYS CFX11.0). The distribution law of relative velocity, static pressure and other important flow parameters in the impeller are captured and compared. 3. Using particle image velocimeter (PIV), the internal flow field of two pairs of centrifugal impellers with long and short blades under five flow conditions is tested and studied, and the relative velocity vector diagram and isoline diagram of the middle section of impeller are obtained. The relative velocity distribution in different impellers is compared and analyzed. 4. The results of numerical simulation and PIV test are compared and the reasons for the difference between the two are analyzed. 5. The design theory of low specific speed and high speed centrifugal pump is introduced. Three sets of composite impellers and volutes with different starting diameters of short blades are designed, and the whole machine mesh of high speed centrifugal pump is divided by unstructured grid. The internal flow field under five flow conditions is numerically simulated. The static pressure field and relative velocity field in the impeller are compared and the influence of the initial diameter of the short blade on the internal flow is analyzed.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311

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