缝隙引流叶轮是基于流动控制思想设计的新型叶轮, 可改善低比转速离心泵的水力性能和空化性能. 测试结果表明: 随着流量的增加, 缝隙引流叶轮离心泵蜗室及出口处的压力脉动和振动都呈先减小后增大的趋势; 在大流量下, 缝隙引流叶轮离心泵的压力脉动和振动明显小于常规叶轮离心泵. 对比分析两种叶轮的内部流动后发现, 缝隙引流叶轮出口处更均匀的速度分布, 及其内部较弱的二次流输运, 均是缝隙引流叶轮离心泵压力脉动小于常规叶轮离心泵的根本原因. 常规叶轮离心泵压力脉动频谱图中的叶频 (blade passing frequency, BPF) 幅值较突出, 而缝隙引流叶轮离心泵的 2 倍叶频幅值较突出. 两种叶轮离心泵的振动频谱分析结果表明, 二者在水平和竖直方向上的振动主频都为 2 倍叶频. 在对压力脉动与振动特性的互相关结果分析中发现, 叶频及倍频的幅值较高, 说明压力脉动和振动密切相关, 同时受到叶轮旋转产生的激励的影响.

Based on the theory of flow control, a gap drainage impeller structure is proposed. Compared with the ordinary impellers, the updated gap drainage impeller can improve hydraulic performance and cavitation performance of centrifugal pump in certain aspects. Experimental results show that, with increase of flow, pressure pulsation and vibration in the volute and outlet region decrease first, and then increase when flow becomes larger. With a large flow, pressure pulsation and vibration of the gap drainage impeller centrifugal pump is obviously weaker than those of the ordinary centrifugal pumps. Numerical investigation shows that the gap drainage impeller has more uniform velocity distribution on the outlet of channel and weaker inner secondary transportation. These are the main reasons for making the pressure pulsation of the gap drainage impeller centrifugal pump weaker. As pressure pulsation is one of the main causes of vibration, the gap drainage impeller can improve operation stability of a low specific centrifugal pump. The main frequency for the ordinary centrifugal pump is the blade passing frequency (BPF). In contrast, the main frequency for the gap drainage impeller centrifugal pump is double BPF, which is the result of a unique gap structure. The main frequency of vibration in horizontal and vertical directions is double BPF. As to mutual correlation of pressure pulsation and vibration, the amplitude of BPF and double BPF is higher, confirming that pressure pulsation and vibration are closely related, and excited by the rotation of impeller.