叶栅稠密度对多叶片轴流泵叶轮内外特性的影响

Study on the Influence of Cascade Density on Internal and ExternalCharacteristics of Multi-Blade Axial-Flow Pump Impeller

为了研究叶栅稠密度对多叶片轴流泵叶轮性能的影响,揭示叶轮进出口基于质量流量加权的速度随叶栅稠密度变化规律的机理,获得叶轮进出口压力脉动随叶栅稠密度的变化规律。采用SST k-ω湍流模型,在特定弦长和特定栅距两种情况下对不同叶栅稠密度多叶片轴流泵叶轮进行了三维非定常数值分析。研究结果表明:在一定范围内,叶轮扬程系数、轴功率与叶栅稠密度均呈正相关分布,效率呈抛物线分布;叶轮进口压力脉动系数随叶栅稠密度的增加呈负相关分布,而叶轮出口反之;此外,叶栅稠密度的增加可有效提高叶片背面最低压强,能明显改善叶轮空化性能;特定栅距下,扬程系数在轮缘叶栅稠密度为1.53时达到最大值0.432,效率在轮缘叶栅稠密度为1.21时达到最大值93.47%;特定弦长下,扬程系数在轮缘叶栅稠密度为1.42时达到最大值0.415,效率在轮缘叶栅稠密度为0.89时达到最大值93.32%;在相同叶栅稠密度下,两种情况的叶轮内外特性呈现较为明显的差异。该研究可为多叶片轴流泵叶轮设计过程中叶栅稠密度的选取提供一定的参考。

To study the influence of cascade density on the performance of the multi-blade axial-flow pump impeller,the mechanism of the variation of the impeller inlet and outlet velocity with cascade density based on mass flow weighting was revealed,and the variation of the impeller inlet and outlet pressure pulsation with cascade density was obtained.The SST k-ωturbulence model was used to numerically analyze the multi-blade axial-flow pump impeller with different cascade densities in two cases:specific chord length and specific pitch.The results show that the impeller head coefficient and shaft power are positively correlated with the cascade density and the efficiency is parabolic in a certain range;the impeller inlet pressure pulsation coefficient is negatively correlated with the increase of the cascade density,while the impeller outlet pressure pulsation coefficient is positively correlated with the increase of the cascade density;in addition,the increase of the cascade density can effectively increase the minimum pressure on the suction surface of the blade,which can significantly improve the cavitation performance of the impeller.For a specific pitch,the head coefficient reaches a maximum value of 0.432 at a peripheral cascade density of 1.53,and the efficiency reaches a maximum value of 93.47%at a peripheral cascade density of 1.21;for a specific chord length,the head coefficient reaches a maximum value of 0.415 at a peripheral cascade density of 1.42,and the efficiency reaches a maximum value of 93.32%at a peripheral cascade density of 0.89.At the same cascade density,the internal and external characteristics of the impeller in the two cases show obvious differences.This study can provide some reference for the selection of cascade density in the design of the multi-blade axial-flow pump impeller.