速度矩分布规律的参数化描述及对混流泵性能的影响

摘要

为提升设计水平、改进混流泵叶片速度矩分布规律的给定,该文通过理论分析,对速度矩分布规律进行参数化表述,选取无量纲速度矩沿流线分布曲线的相对系数a0与速度矩分布曲线在叶片出口处的导数值P作为速度矩分布参数.基于混流泵叶轮正反问题迭代法设计平台,给定不同速度矩分布参数组合设计了一系列混流泵叶轮.基于SIMPLEC算法,通过求解N-S方程和RNG k-ε湍流模型方程,对混流泵叶轮内部三维湍流流场进行了模拟,获得了相对速度与压力分布,并预估了水力效率.研究表明,速度矩分布参数直接影响着叶片包角与出口边位置,进而影响到叶轮内部相对速度与压力的分布以及流动的稳定性.合理选择速度矩分布参数,有利于增强叶片对于流体运动的控制能力,改善叶轮内部压力分布,使叶轮具有更为优越的水力特性.该文提出的速度矩分布规律参数化方法,为混流泵叶轮设计过程中速度矩分布规律的给定提供了有益的借鉴.%To parameterize the velocity moment distribution, Parameter α0, relative coefficient of the distribution curve of the dimensionless velocity moment along the streamline, and parameter P, curve derivative value in the position of blade trailing edge, were selected to be velocity moment distribution parameters by theoretical analysis. Based on the design platform of iterative calculation of direct and inverse problems of the mixed-flow pump impeller, a series of mixed-flow pump impellers were designed with different combinations of velocity moment distribution parameter values. By solving N-S equation and RNG k-e turbulent model equation, the three-dimensional turbulent flow field inside the mixed-flow pump impeller was simulated on the basis of SIMPLEC algorithm. Thus, the relative pressure and the relative velocity distributions were determined and the hydraulic efficiency was estimated. The results show that, velocity moment distribution parameters have direct influences on the blade wrap angle and the trailing edge, which has further effects on the internal relative velocity distribution, the internal relative pressure distribution and flow stability. Reasonable selection of velocity moment parameters can strengthen the control of blade over fluid motion, improve internal pressure distribution of impeller and realize better hydraulic characteristics of the impeller. In addition, the parameterization method of the velocity moment distribution developed in this paper can also be beneficial to setting the velocity moment distribution though the procedure of impeller design of the mixed-flow pump.