不同载荷分布型式下轴流泵叶顶间隙流特性研究

轴流泵叶顶泄漏流对水泵内外特性有重要影响，从控制叶片载荷角度建立了轮缘载荷分布型式与叶顶泄漏流的关系。基于三维反问题设计方法设计得到了具有前载、中载和后载3种典型轮缘载荷分布型式的轴流泵叶轮模型，采用三维湍流模拟技术研究了上述3种轮缘载荷分布型式对轴流泵叶顶泄漏流及其诱导的泄漏涡流动的影响。结果表明，相对于轮缘前载型叶轮和轮缘中载型叶轮，轮缘后载型叶轮可有效消除叶片进口附近低压区，有利于叶轮空化性能；小流量工况性能有所提高，有效抑制流量扬程曲线的驼峰现象；同时轮缘后载型叶轮具有更好的小流量工况压力脉动性能。

Numerical Study of Blade Loading Effects on Tip Leakage Flow in Axial-flow Pump

The tip leakage flow of axial-flow pump has an important influence on the internal and external characteristics of the pump. The relationship between the blade loading distribution patterns and tip leakage flow was established from the perspective of controlling the blade load. Based on the three-dimensional inverse problem design method, the impeller models of axial-flow pump with three typical blade loading distribution patterns of front load, middle load and after load at the blade tip were obtained. The influence of the blade loading distribution on tip leakage flow and induced leakage vortex flow of the axial-flow pump was studied based on three-dimensional turbulence simulation technique. It was found that compared with the front-loading type impeller and the middle-loading type impeller, the after-loading type impeller can effectively eliminate the low-pressure area near the blade inlet, which was beneficial to the cavitation performance of the impeller. The external performance simulation results showed that the pump performance was improved at the small flow rate and the hump phenomenon of the discharge-head characteristic curve was effectively suppressed, which was consistent with the experiment results. At the same time, the impeller with after load had better pressure pulsation performance under the condition of small flow rate.