螺旋离心泵轴向力的数值计算与分析

针对螺旋离心泵轴向力求解时,数学模型建立和方程难以封闭等问题,为了实现螺旋离心泵轴向力的定量求解,研究其轴向力受介质的影响和随介质的变化规律,以150×100LN-32型螺旋离心泵为研究对象,选用清水和两相流含沙水作为介质,应用计算流体力学软件Fluent,建立相对坐标系下的时均连续方程及Navier-Stocks方程,并采用标准k-ε方程湍流模型和SIM-PLE算法进行数值模拟,得到螺旋离心泵内流场的压力分布后计算出轴向力,从而避开了单纯数学上定量求解螺旋离心泵轴向力的许多难题.在此前提下,通过研究在固液两相流介质中,颗粒体积分数、颗粒直径及不同的流量对轴向力的影响和变化规律,结果表明：螺旋离心泵的轴向力随两相流介质体积分数的增大而增大;随流量和颗粒粒径的增大反而减小.该结论对于提高螺旋离心泵的稳定性和延长其使用寿命具有重要意义.

Numerical calculation and analysis on axial thrust in screw centrifugal pump

When the axial thrust is estimated in a screw centrifugal pump under solid-liquid two-phase flow conditions by means of ordinary analytical methods,there exists problems,such as mathematic models establishment of flow and difficulties in closure of the models.Thus in order to predict the axial thrust precisely and to correlate it to the physical property parameters of the medium handled by the pump,the axial thrust in the screw centrifugal pump of type 150×100LN-32 was calculated when it transported a sand-water two-phase fluid by using CFD code-Fluent.The two-phase flow in the pump was described by the time-averaged Navier-Stokes equations in relative coordinate systems and the mixture model.The standard k-ε two-equation turbulence model and the SIMPLE algorithm were used in numerical simulations.An axial thrust was calculated after the pressure distributions in the pump were available.In this way,the problems and the difficulty aforementioned can be avoided.The relations of axial thrust to solid volume fraction,particle diameter and flow rate of the two-phase flow were explored by using the computational results.The results showed that the axial thrust rises with increasing solid volume fraction,but reduces with increasing flow rate and particle diameter.The conclusion is of great significance for improving the stability of the pump and extending its lifespan.