多级离心泵首级叶轮停机特性数值研究

针对多级离心泵在突然断电情况下可能出现的意外事故问题,基于滑移网格技术、用户自定义函数和SIMPLE算法,在关死点处和给定转速下降规律情况下,对一多级离心泵首级叶轮的停机过程进行了内部非定常粘性流动的数值模拟,通过数值计算获得了多级离心泵首级叶轮停机过程的外特性和内部流场演化特性,重点分析了叶轮进口、叶轮出口和反导叶出口3个位置处的瞬态物理量变化。研究结果表明,无量纲扬程系数在停机之前和停机过程前期阶段基本不变,而在停机过程末期迅速下降,叶轮停止转动时,各个物理参数并未同步趋零,总之表现出明显的瞬态行为特征;叶轮出口处的物理量参数变化受叶轮转动影响最大,其次受叶轮进口处的参数变化影响,而反导叶出口处的参数变化最小。

Numerical study on transient stopping characteristics of the first stage impeller of a multistage pump

Aiming at the accident problems that may occur at the multistage centrifugal pump under the condition of sudden power lost,a prototype multistage centrifugal pump was employed as object to calculate the internal unsteady flow inside pump model during stopping period under the condition of shut-off and the given rotating speed decrease,wherein the sliding mesh technology,the user defined function (UDF) and SIMPLE algorithm were employed to compute the flow inside the first stage impeller of the multistage centrifugal pump.The evolution characteristics against time of the external performance and the internal flow fields were obtained through numerical calculation,wherein the variable characteristics of physics parameters at the inlet and outlet of the first stage impeller and at the outlet of the reverse guide vane were emphasized.The results indicate that the non-dimensional instantaneous head is basically unchanged before stopping and at the earlier stage of stopping,and quickly falls at the later stage of stopping.In conclusion,this displays the pronounced transient behavior.The influence of the rotating effect on the physical parameters at the impeller outlet is most remarkable,the parameter variations at the impeller inlet is second,while that at the outlet of the negative guide-blades is lightest.