基于圆周分速度的轴流泵优化设计研究

Optimization Design of Axial Flow Pump Based on Circumferential Velocity

摘要: 针对轴流泵进行水力性能设计和优化，在满足设计要求的基础上，实现其水力效率的提升。以比转速ns = 1250的轴流泵为对象，采用CFD数值模拟方法，借助于N-S基本控制方程和标准k-ε双方程湍流模型，对轴流泵进行了全流道数值模拟，统计其速度环量的变化规律，分析总结其外特性，研究其内部流动特征。通过解决实际过程中轴流泵扬程偏低的原因，提出圆周分速度修正系数，并选取了合适的圆周分速度修正系数来优化模型。根据优化结果可见，优化之后，轴流泵的水力性能得到明显提升，满足设计要求工况，扬程从2.729 m提高到3.44 m，水力效率从80.35%提高到82.69%，同时高效区明显扩大。从内部流动分析得出，优化之后叶轮内部流体流态稳定，无脱流、旋涡等现象，流速均匀分布。在轴流泵叶轮设计过程中，宜采用变环量设计，减小轮毂处的环量，同时增大轮缘处的环量。

Abstract: Hydrodynamics design and optimization were conducted for an axial flow pump. On the basis of meeting the design requirements, the hydraulic efficiency was improved. Taking the axial flow pump with specific speed ns = 1250 as the object, using the CFD numerical simulation method, the numerical simulation method of the N-S basic control equation and the standard k-ε double equa-tion turbulence model was used to simulate the whole flow channel of the axial flow pump, the change regulation of its velocity circulation was counted; the external characteristics of the axial flow pump were analyzed and the internal flow characteristics were studied. The circumferential velocity correction coefficient was proposed by solving the problem of low lift of an axial flow pump in practical process, and the appropriate circumferential velocity correction coefficient was selected to optimize the model. The results show that after optimization, the hydraulic performance of the axial-flow pump has been significantly improved to meet the design requirements, the head has been increased from 2.729 m to 3.44 m, the hydraulic efficiency has been increased from 80.35% to 82.69%, and the high efficiency area has been significantly expanded. From the analysis of internal flow, it is concluded that the flow pattern in the impeller is stable after optimization, and the flow velocity distribution is uniform without the phenomena of shedding and vortex. In the process of axial flow pump impeller design, variable circulation design should be adopted, which should reduce the circulation at the hub and increase the circulation at the flange.