Relationship between Axial Width and Flow Characteristics of Pump Chamber in Double Volute Centrifugal Pump

双蜗壳离心泵泵腔轴向宽度与流动特性的关系

¹ College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, China
² Institute of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an 710048, China
³ Xi'an Pump & Valve Plant Co., Ltd, Xi'an 710025, China

Received: 7 January 2020

Abstract

The axial width of pump chamber has a great influence on the flow characteristics of the pump chamber in the centrifugal pump. A single-stage single-suction double volute centrifugal pump with a semi-open impeller was selected as the object. For the 6 different pump chamber axial width, it was concluded that the pump chamber pressure at the different angles (0°, 90°, 180°, 270°) along the radial variation characteristics according to the contrast analysis of the pump cavity pressure field, velocity field distribution. The correlation between the pump chamber pressure and the impeller radius was revealed. The tangential velocity and radial velocity along the axial distribution curves were draw. The results show that when the axial width of pump chamber increases from 23.9 mm to 43.9 mm, the pressure value of the same radial position increases gradually. The radial pressure difference is decreasing. At the same axial width of pump chamber, the pressure mean increases along the radial approximately parabola. The tangential velocity of different angular directions has little difference in axial distribution. The mean of dimensionless tangential velocity in the turbulent core area decreases from 0.32 to 0.19 with the increasing of pump chamber axial width. The radial velocity varies is greatly along the axial direction. There are eddies at the directions of 0ånd 180°, but the mean of radial velocity in the turbulent core area is about 0. This research provides the reference for centrifugal pump hydraulic design, structural design and the accurate calculation of axial force.

摘要

离心泵泵腔轴向宽度对泵腔液体流动特性具有较大影响，选取单级单吸半开式叶轮双蜗壳离心泵为研究对象，在6种不同泵腔轴向宽度条件下，对比分析泵腔压力场、速度场分布规律，得出泵腔压力在不同角度（0°，90°，180°，270°）沿径向变化特征，揭示泵腔压力与叶轮半径关联性，绘制切向速度、径向速度在不同角度沿轴向分布曲线。结果表明：当泵腔轴向宽度由23.9增大至43.9 mm时，同一径向位置的压力值逐渐增大，径向压差不断减小；同一泵腔轴向宽度下，压力均值沿径向近似呈抛物线且不断增加。不同角度方向的切向速度沿轴向分布差别较小，且湍流核心区无量纲切向速度均值随泵腔轴向宽度的增大逐渐由0.32减小到0.19；不同角度方向的径向速度沿轴向分布差别较大，0°和180°方向上存在涡流，但湍流核心区径向速度均值近似为0。该研究为离心泵水力设计、结构设计和准确计算轴向力提供了有力的依据。