基于CFD的中高比转速离心泵叶轮设计方法研究

发布时间：2019-02-08 17:05

【摘要】：中高比转速离心泵的叶轮设计多采用一元理论，且少有研究，本文采用二元有势流动理论设计中高比转速离心泵叶轮，并与传统的采用一元理论设计的叶轮进行对比，分析其内部流动及外特性。本文采用CFD计算软件Fluent6.3，对基于两种设计方法的叶轮的流体计算域模型进行全流场三维湍流数值模拟，旨在研究叶轮二元理论（ωu=0）的设计，对比叶轮内部流动状态以及对其性能的影响规律，本课题的主要研究内容和所做的主要工作如下： 1、根据离心泵的基本设计参数，首先基于传统的离心泵一元设计理论，设计了1号叶轮；然后基于ωu=0的二元设计理论，选取了六种速度矩分布规律，完成了2号~7号叶轮的水力设计。 2、对设计得到的七个叶轮方案进行精确的全流道三维实体造型和网格划分，为全流道内部流动CFD数值模拟计算及其性能预测的准确性奠定可靠的基础。 3、CFD数值模拟采用雷诺时均Navier-Stockes方程和标准k ε湍流模型，利用SIMPLEC算法，对采用两种设计理论设计的七个叶轮的离心泵进行了全流场数值模拟，进一步处理1号～4号模型的计算数据，得到叶片沿轴面流线的轴面速度和速度矩分布，，将不同叶轮设计理论假设的速度分布与真实流场的速度分布进行了对比分析。 4、分别对采用一元理论和二元理论设计的叶轮的离心泵，在0.4Q、0.6Q、0.8Q、1.0Q、1.2Q等不同流量运行工况进行了数值模拟对比，得到了1号～4号模型方案内部流场的压力分布和速度分布，比较了两种方案的外特性数值模拟结果。本课题的主要创新点如下： 1、采用二元理论设计了中高比转速离心泵叶轮，对比分析了两种设计理论的假设与真实流动规律的差异。 2、设计出了一个较为接近二元有势流动规律的叶轮，对比分析了叶轮内部流体进出口速度矩值与叶轮能量头和效率的关系。由于时间、条件和本人经验不足所限，本课题做的工作有限，有很多工作目前还没有进行到位。文中给出的基于二元设计理论的叶轮的水力设计，尤其是叶片上速度矩的取值和分布，还有很大的提升空间，有待于以后继续深入研究和探讨。
[Abstract]:The impeller design of medium and high specific speed centrifugal pump is mostly based on the monadic theory, and few studies have been done. In this paper, binary potential flow theory is used to design the impeller of the centrifugal pump with middle and high specific rotational speed, and it is compared with the traditional impeller designed by univariate theory. Its internal flow and external characteristics are analyzed. In this paper, three dimensional turbulent numerical simulation of impeller fluid computational domain model based on two design methods is carried out by using CFD software Fluent6.3,. The purpose of this paper is to study the design of impeller binary theory (蠅 UO). Comparing the internal flow state of impeller and the influence law on its performance, the main research contents and main work of this subject are as follows: 1. According to the basic design parameters of centrifugal pump, firstly, based on the traditional centrifugal pump monolithic design theory, The impeller No. 1 is designed. Then based on the dual design theory of omega 0, the hydraulic design of impeller No. 2 ~ 7 is completed by selecting six laws of velocity and moment distribution. 2. The three dimensional solid modeling and mesh division of the seven impeller schemes were carried out, which laid a reliable foundation for the CFD numerical simulation of the flow inside the channel and the accuracy of the performance prediction. Using Reynolds time averaged Navier-Stockes equation and standard k 蔚 turbulence model, the full flow field of a centrifugal pump with seven impellers designed by two design theories was simulated by using SIMPLEC algorithm. Further processing the calculation data of model 1 ~ 4, the axial velocity and velocity moment distribution of blade along the axial streamline are obtained. The velocity distribution of different impeller design theory hypotheses is compared with the velocity distribution of real flow field. 4. The centrifugal pump with impeller designed by univariate theory and binary theory is numerically simulated and compared under different flow operating conditions, such as 0.4Q0. 6Q / 0. 8Q / 1. 2Q, etc. The pressure distribution and velocity distribution of the flow field in model No.1 ~ 4 are obtained and the numerical simulation results of the external characteristics of the two schemes are compared. The main innovations of this paper are as follows: 1. The impeller of centrifugal pump with medium and high specific speed is designed by using binary theory, and the differences between the hypotheses and the real flow laws of the two design theories are compared and analyzed. 2. A impeller which is close to the law of binary potential flow is designed, and the relationship between the inlet and outlet moment of fluid and the energy head and efficiency of impeller is compared and analyzed. Due to the limitation of time, condition and experience, the work of this subject is limited, and a lot of work has not been done yet. In this paper, the hydraulic design of impeller based on binary design theory, especially the value and distribution of velocity moment on blade, still has a lot of lifting space, which needs to be further studied and discussed in the future.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH311

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