中文摘要：

基于LES模型模拟混流式核主泵在设计工况下的非定常特性,着重分析了叶轮进口处以及导叶接近出液管附近各流道内的非定常流动特征。研究表明：叶轮进口中心测点上叶频的三次谐波振幅相对较为明显,表明叶轮与导叶之间的动静干涉作用在叶轮进口中心处相对而言更加明显;导叶流道3与流道2相对压差较大,该流道正对球形壳体出液管附近,说明一个旋转周期内导叶的这两个流道内压力分布较为不均匀,其原因应与流道所处位置有关,在这两个流道附近存在较大的流动分离和回流;虽然在流道3内的压力系数波动最大,但叶轮对导叶流道3的干涉作用却相对于其他两个流道是最小的,进一步说明正对球形出液管附近的导叶流道内部流动较为复杂。

英文摘要：

Based on Large Eddy Simulation（LES） turbulent model,the unsteady flow characteristics in mixed-flow nuclear reactor coolant model pump were simulated.The impeller inlet and the flow channels of the diffuser,especially,flow channels near the casing outlet are investigated by numerical simulation.Based on results obtained from the LES turbulent model in the design of operating conditions,it is clear that the monitoring point at center of the impeller inlet,the peak values in pressure spectra are caused by the three times blade frequency.It is indicated that the interference effect between impeller and diffuser are more obvious at the center of impeller inlet.The pressure coefficient difference values of diffuser flow passage 3 and 2 have higher values,relatively.And these two flow channels are closed to the spherical casing outlet,indicating the pressure distribution of the two flow channels are more asymmetrical than any other channels,the reason may be related to the position of the flow channel.There may have some large flow separation or backflow near these two flow channel.Although the pressure coefficient difference value in the flow channel 3 is maximum value,the interference effect between impeller and diffuser flow channel 3 compared with the other two channels is minimal,which further demonstrates the flow channel position,especially near the casing outlet,the internal unsteady flow is more complex.