颗粒密度对动静叶栅内流动特性的影响

基于大涡模拟方法和Mixture多相流模型,运用CFD软件对泵工况下动静叶栅内的固液两相非定常流场进行了数值计算,分析了不同颗粒密度下动静叶栅内固液两相流动特性及流道内涡结构的演化规律。结果表明,颗粒密度增加时,离心泵扬程和效率出现小范围的增加;动叶栅进口负压区面积逐渐增大,静叶栅出口处压力逐渐增大;叶轮流道内旋涡个数增多;叶轮进口固相体积分数增大,固体颗粒在叶轮进口聚集。动叶的强剪切和较大逆压梯度作用是动静叶栅内涡流产生和演化的主要因素。

Effect of Grain Density on Flow Characteristic in Dynamic and Stator Cascade

Solid-liquid two phase unsteady flow field in dynamic and stator cascade under working condi-tion of pump is numerically simulated with CFD software based on large eddy simulation and Mixture mul-tiphase flow model,analyzing solid-liquid two phase flow characteristic in dynamic and stator cascade under different grain density and evolution rule of inner vortex structure in flow passage.The calculated results show that with grain density increasing,centrifugal pump lift and efficiency increase in a small scale;zone area of negative pressure in inlet of dynamic blade grid gradually increases,while pressure at exit of stator cascade increases;number of inner vortex in impeller passage increases;solid phase volume fraction in im-peller inlet increases,so solid particles gather at inlet of impeller.Strong shear of dynamic cascade and big-ger adverse pressure gradient is main factor for generating inner vortex and its evolution in dynamic and stator cascade.