大型立式混流泵装置水动力特性数值模拟

应用k-ε和k-ω相结合的SST湍流模型封闭控制方程,对立轴蜗壳式混流泵装置的内部流动结构进行数值模拟。采用全隐式网格耦合求解,计算中考虑了叶轮叶顶间隙的影响。通过计算获得了泵装置全流场,分析了蜗壳出水室的流态和叶轮的水力特性,预测了泵装置性能并与试验值进行了比较。结果表明：蜗壳出水室内的流动为轴向流动与环向旋转的合成流动,静压分布较对称,出口断面轴向流速分布均匀度和速度加权平均角相对较低;叶片表面的静压分布呈现较为清晰的规律,叶片表面静压分布比较均匀,压力面的静压整体上比吸力面要高;随着流量的增大,叶轮承受的轴向力渐小,而径向力则先减小后增大;数值模拟预测的性能结果与试验的性能结果相比较,前者高于后者,趋势基本一致。

Numerical analysis on hydrodynamics of large-scale mixed-flow pump system

Three-dimensional fluid flow inside a mixed-flow pump system is studied using the shear stress transport(SST) turbulent equations of combined k-ε and k-ω models,with the governing equations solved by a fully-coupling implicit method,focusing on the flow pattern in the volute passage of double helixes and the hydraulic characteristics of impeller.Results show that the flow in the volute passage takes spiral pattern of combined axial and rotary flows and that the static pressure distribution is symmetric.At the outlet,the uniformity of axial velocity is poor and the velocity-weighted average swirl angle is relatively low,and on the blades the static pressure has a regular distribution,higher on its pressure side than its suction side.As flow rate increases,the axial force of runner decreases gradually,while the radial force decreases first and then increases.The calculated performance curves are close to the measurements.