高速磁悬浮离心风机气动部分设计和仿真

发布时间：2019-05-17 00:32

【摘要】：离心风机在社会应用中扮演着十分重要的作用,由于其能耗低、转速高、容积效率高且输送气体清洁干净等优点,被广泛地应用于化工厂、电厂以及建筑等场所的通风换气、排烟降温以及处理污水中。在二级污水处理工艺系统中,风机是曝气流程系统的重要设备,风机的效率是最重要的技术经济指标,其电耗占污水处理厂全部电耗的50%-60%。目前国内的风机,大部分还处于3000r/min的转速水平,由于机械轴承的摩擦造成效率偏低。为此,专门研发新型高速磁悬浮离心风机,合理设计叶轮的样式以及结构尺寸,采用SOLIDWORKS绘图软件精确绘制叶轮及蜗壳的三维图形,应用CFD流动分析软件和SIMPLE算法,直观描述离心风机内部三维粘性流场,根据模拟数据与计算数据之间的对比验证风机设计。文章首先介绍了高速离心风机与其他类型风机比较所具有的突出优点,随后,论述了计算流体力学的理论知识和基本原理,并详细地介绍了通用的FLUENT软件的基本功能及特点。第三章介绍了叶轮内流体的基本方程以及叶轮选型的依据,然后推导出离心风机气动部分的结构计算式,对部分参数选取合理的预选初值,并用MATLAB对计算过程进行编程,最终计算出包括叶片数、级数、叶轮进出口直径以及叶轮转速等参数。第四章以这些参数值为预选值,应用SOLIDWORKS搭建高速风机叶轮、扩压器以及蜗壳等部分的三维模型,并将这些模型的STEP文件导入GAMBIT软件中,采用TET/HYBRID网格单元、TGRID网格类型以及合适的网格尺寸对这些模型进行网格划分。文章的最后部分,介绍了本模型采用的几种FLUENT边界条件并详述了设定过程。随后,采用分离隐式求解器,应用标准k-ε两方程湍流模型,对高速磁悬浮离心风机气动部分进行了数值模拟,将仿真计算获得的叶轮进出口压力、叶轮出口圆周速度矢量以及湍动能等参数的值与对应的设计预选值进行了分析和比较。结果表明,数值模拟计算出来的结果与设计预选数据基本吻合,验证了本文模型设计的合理性,即本文前面经过公式推导设计的叶轮、扩压器以及蜗壳的结构尺寸能够满足项目要求。应用本文提供的设计公式和建模方法完全可以设计出符合预期效果的高速离心风机气动部分的结构尺寸,并可以用于工程实际。本课题的研究为新型高速磁悬浮风机的设计提供理论依据,对于提高高速离心式风机的设计水平具有重要意义。
[Abstract]:Centrifugal fan plays a very important role in social application. Because of its low energy consumption, high rotating speed, high volume efficiency and clean transportation gas, centrifugal fan has been widely used in ventilation and ventilation in chemical plants, power plants, buildings and other places. Exhaust smoke and cool down and treat sewage. In the secondary sewage treatment process system, the fan is an important equipment of the aeration process system, and the efficiency of the fan is the most important technical and economic index, and its power consumption accounts for 50% of the total power consumption of the sewage treatment plant. At present, most of the domestic fans are still at the speed level of 3000r/min, and the efficiency is low due to the friction of mechanical bearings. For this reason, a new type of high speed maglev centrifugal fan is specially developed, the style and structure size of impeller are reasonably designed, the 3D graphics of impeller and volute are accurately drawn by SOLIDWORKS drawing software, and the flow analysis software CFD and SIMPLE algorithm are used. The three-dimensional viscous flow field in centrifugal fan is described intuitively, and the fan design is verified according to the comparison between simulation data and calculation data. This paper first introduces the outstanding advantages of high speed centrifugal fan compared with other types of fan, then discusses the theoretical knowledge and basic principle of computational fluid mechanics, and introduces in detail the basic functions and characteristics of general FLUENT software. In the third chapter, the basic equation of fluid in impeller and the basis of impeller selection are introduced, then the structure calculation formula of pneumatic part of centrifugal fan is deduced, the reasonable initial value of pre-selection of some parameters is selected, and the calculation process is programmed with MATLAB. Finally, the parameters including blade number, series, impeller inlet and outlet diameter and impeller speed are calculated. In the fourth chapter, taking these parameter values as pre-selected values, the 3D models of high speed fan impeller, diffuser and volute are built by SOLIDWORKS, and the STEP files of these models are imported into GAMBIT software, and TET/HYBRID grid element is used. These models are meshed by TGRID grid type and appropriate grid size. In the last part of the paper, several FLUENT boundary conditions used in this model are introduced and the setting process is described in detail. Then, the pneumatic part of the high-speed maglev centrifugal fan is simulated by using the separation implicit solver and the standard k-蔚 two-equation turbulence model, and the inlet and outlet pressure of the impeller is calculated by the simulation. The values of circumferential velocity vector and turbulent kinetic energy at the outlet of impeller are analyzed and compared with the corresponding design preset values. The results show that the results calculated by numerical simulation are in good agreement with the pre-selected data of the design, which verifies the rationality of the design of the model in this paper, that is, the impeller designed by formula derivation in front of this paper. The structure and size of diffuser and volute can meet the requirements of the project. The structure size of the pneumatic part of the high speed centrifugal fan which accords with the expected effect can be designed by using the design formula and modeling method provided in this paper, and can be used in engineering practice. The research of this paper provides a theoretical basis for the design of a new type of high-speed maglev fan, and is of great significance to improve the design level of high-speed centrifugal fan.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH432

【参考文献】