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为解决离心泵停机过程数值模拟时施加边界条件的困难,建立了一个包含离心泵在内的封闭循环管路系统从而实现自耦合求解。结果显示:停机过程中流量下降历程滞后于转速下降历程,而扬程下降则较为迅速;液流角或叶片冲角的持续改变是内部流动出现持续变化的直接原因;动静干涉效应使得稳定运行工况下的流量呈现微小波动特征,而非恒定值;停机过程表现出明显的瞬态效应,准稳态假设无法适用于停机过程精确瞬态行为预测。借助于CFD技术初步揭示了离心泵停机过程中的瞬态特性,为其它叶轮机械的瞬态行为研究提供了很好的借鉴与参考。
In order to solve the difficulty of applying boundary conditions during the numerical simulation of centrifugal pump shutdown, a closed loop piping system including centrifugal pump was established to realize self-coupling solution. The results show that the flow decline during the shutdown process lags behind the rotation speed decline and the head lift is relatively rapid. The continuous change of the flow angle or the blade angle is the direct reason for the continuous change of the internal flow. The static and dynamic interference effect makes the steady operation condition Under the condition of low flow rate, the flow shows little fluctuation instead of constant value. The shutdown process shows obvious transient effect, and the quasi-steady state assumption can not be applied to predict the exact transient behavior during shutdown. By means of CFD technology, the transient characteristics of the centrifugal pump during shutdown are revealed, which provides a good reference for the research of transient behavior of other impeller machines.