非定常大涡模拟下混流泵叶轮的轴向力研究

为研究导叶式混流泵的轴向力,建立了导叶式混流泵内全三维流道模型,基于非定常大涡模拟亚格子尺度模型与滑移网格技术,对不同工况下的混流泵进行了数值模拟和性能预测,并将非定常方法计算值、定常方法计算值、经验公式估计值与试验值进行比较分析。结果表明:非定常方法计算得到的叶轮轴向力变化规律与试验和经验公式计算得到的轴向力变化规律更接近;在设计工况附近,定常和非定常方法计算得到的混流泵叶轮轴向力的数值与试验值的相对误差均约为10%;在小流量及大流量工况下,定常方法的计算值与试验值的相对误差约为30%,非定常方法的计算值与试验值的相对误差在10%之内。因此,非定常模拟方法可以更准确地预测混流泵的轴向力。

Study of Axial force on Impeller of Mixed-Flow Pump by unsteady Large Eddy Simulation

With an attempt to investigate the axial force on impeller of mixed-flow pump,the mathematic model of three dimensional flow for guide vane mixed-flow pump was established. In order to predict the pump's performance and compare the steady simulation values,unsteady calculation values and empirical formula values with the experimental calculation values,the numerical simulation and performance prediction were carried out based on the unsteady large eddy simulation,subgrid-scale model and sliding grid technique. The results of showed that using the unsteady method to calculate the values of axial force on impeller is closer to the experiment values and empirical formula values; under the design conditions,the axial force's relative errors calculated by steady and unsteady simulation and the experimental calculation errors were both about 10 %;under low flow conditions as well as high flow conditions,the axial force on impeller relative errors of steady simulation were about 30 %,whereas the relative errors of unsteady simulation were about 10 %,compared with experimental calculation errors. Therefore,unsteady method can predict the axial force on impeller of mixed-flow pump more accurately.