Rotating stall in centrifugal pumps takes place frequently under part-load conditions, along with high pressure pulsation. The major focus for studies is rotating stall inside the impeller, rarely paying attention to that in the vaned diffuser. In this study, rotating stall behavior in a vaned diffuser centrifugal pump has been numerically investigated, and the cross-power spectrum method is adopted to identify low-frequency pressure signals. The applied numerical method has been validated by experimental results including flow structures provided by PIV measurements. For the vaned diffuser pump, a hump region in head curve is observed between 0.25Q_d and 0.5Q_d conditions. Under 0.41Q_d condition, rotating stall occurs in the vaned diffuser of the pump, with three stall cells rotating opposite to the direction of impeller rotation and the rotating frequency being 0.083 Hz equal to 1/600 of the impeller rotating frequency. Rotating stall takes place under 0.5Q_d condition as well, whereas only a periodic process of stall cell from inception to disappearance appears in the diffuser channel under 0.35Q_d condition. Furthermore, the effect of number of diffuser vanes on rotating stall characteristics has been analyzed in detail.

离心泵的旋转失速经常发生在部分负载条件下，同时伴随着高压脉动。研究的主要重点是叶轮内的旋转失速，很少注意叶片式扩压器中的失速。在这项研究中，对叶片式扩散离心泵的旋转失速行为进行了数值研究，并采用交叉功率谱方法来识别低频压力信号。应用的数值方法已经通过包括PIV测量提供的流动结构在内的实验结果进行了验证。对于叶片式扩散泵，在0.25 Q _d和0.5 Q _d条件之间观察到扬程曲线中的驼峰区域。低于0.41 Q _d在这种情况下，泵的叶片式扩散器中发生旋转失速，三个失速单元与叶轮旋转方向相反，旋转频率为0.083 Hz，等于叶轮旋转频率的1/600。旋转失速也发生在0.5 Q _d的条件下，而扩散室在0.35 Q _d的条件下仅出现了从开始到消失的失速细胞的周期性过程。此外，已经详细分析了扩压器叶片数量对旋转失速特性的影响。