轴流泵叶轮非线性环量数学模型建立与试验

Establishment and Experiment on Nonlinear Circulation Mathematical Model of Axial Flow Pump Impeller

摘要:

以轴流泵叶轮出口速度梯度方程和轴面速度表达式为基础，建立了轴流泵叶轮非线性环量数学模型，并推导了叶片出口流动方程式。采用微型五孔球形探针，对南水北调工程用轴流泵模型（TJ04—ZL—06）最优工况下叶轮出口不同半径位置的环量和轴面速度分别进行了试验测量。试验结果表明，高效轴流泵叶轮出口环量呈现非线性分布，在叶片中部较为平直，在轮毂侧环量降低至中部的0.8倍左右，而轮缘侧增大至中部的1.2倍左右；同时叶轮出口轴面速度分布呈现抛物线流型，叶片中部速度最大。基于建立的非线性环量数学模型对叶轮出口轴面速度分布进行了计算，结果表明不同半径的轴面速度计算值与试验值误差均小于5%，验证了数学模型的可靠性。

关键词:轴流泵;非线性环量;数学模型;流动测量

Abstract:

The nonlinear circulation mathematical model of axial flow pump impeller was established based on the independence assumption of the cylindrical layer, the velocity gradient equation and meridional velocity equation in axial-flow impeller outlet. Miniature five-hole spherical probe was used to measure circulation and meridional velocity of South-to-North Water Diversion Project axial flow pump model (TJ04—ZL—06) in the blade outlet at the optimal condition. The experimental results show that the nonlinear circulation distribution appears in the axial flow impeller outlet. The circulation curve is relatively flat in the central of blade, while it reduces to about 0.8 times near hub and increases to about 1.2 times near tip. The meridional velocity distribution shows parabolic flow pattern and the maximum velocity appears in the middle of blade. The meridional velocity in blade outlet was calculated based on nonlinear circulation mathematical model. The results show that the calculated values show agreement with the experimental results, and the calculation errors of different radius points are less than 5%.

Key words:Axial-flow pump;Nonlinear circulation;Mathematical model;Flow measurement