农业工程学报Issue(23)：86-93,8.DOI:10.3969/j.issn.1002-6819.2014.23.012
不同叶顶间隙对斜流泵性能影响的数值分析
Numerical analysis for effects of different blade tip clearance on performance in mixed-flow pump
摘要
Abstract
The mixed-flow pump has some good characteristics, such as high efficiency, good start performance, and wide working condition. The traditional design methods of mixed-flow pumps cannot evaluate the sensitivity of the tip clearance’s impact on pump performance quantificationally. In order to reveal the tip clearance effect on the internal flow field and the performance of mixed-flow pump, and given the selection range of blade tip clearance, four mixed-flow pumps with different tip clearance values, 0, 0.5, 1.0, and 1.5 mm, respectively, were studied. The distorted triangle method was adopted to design the impeller and guide vane, and based on the software ICEM CFD to generate block hexahedron structured grids of the computational domain, and then the topological structure of the grids of the blade tip region was optimized. The internal flow field of the pumps was simulated based on the SST k-ωturbulence model and SIMPLEC algorithm, using the structured grid technology mentioned above, and the numerical simulation results were compared with the test experimental data, which agreed well with each other. The results show that the value of tip clearance have a significant effect on mixed-flow pump hydraulic performance, when tip clearance was 0.5 mm. The head-flow positive slope characteristic of the pump can be suppressed effectively, and the efficiency value of mixed-flow pump is highest at this time; when tip clearance was 0, the pump head-flow positive slope characteristic is relatively obvious;when tip clearance was 1mm, simulation values and experimental values matched well, so the SST k-ωmodel can simulate the flow characteristics of tip clearance of mixed-flow pumps well, so that the results of the performance prediction have some credibility. Under small flow conditions, small tip clearance values can restrain unstable positive slope features of mixed-flow pump. When tip clearance was 0.5mm, the performance of the pump with small tip clearance is the best. With the increasing of tip clearance value, tip leakage flow became outstanding gradually, the axis plane flow velocity of the near wall region of the impeller outlet and the vorticity change significantly, which indicates that tip clearance affects the axis plane velocity distributions of the impeller and the load distributions of the blades directly. As influenced by the frictional resistance and the viscous resistance of the wall, the impeller axis plane flow velocity of the impeller hub region and tip clearances areas is relatively small. When tip clearance increase, blades load of the impeller hub region and tip clearances areas decay rapidly, and it affects the performance ability of impeller blades. At the same time, serious mix permeability and entrainment effects come into being between the leakage flow near the blade tip and the main stream flow, and cause the significant decline in the axis plane flow velocity in the region near the blade tip of impeller outlet. At the moment, the jet effect of the tip leakage flow decays gradually, and the sphere of influence gradually extends to the entire blade tip region.关键词
泵/数值分析/流场/斜流泵/叶顶间隙/泄漏流动/外特性Key words
pumps/numerical analysis/flow fields/mixed-flow pump/tip clearance/leakage flow/external characteristic分类
机械制造引用本文复制引用
黎义斌,胡鹏林,李仁年,李鹏辉,毕祯..不同叶顶间隙对斜流泵性能影响的数值分析[J].农业工程学报,2014,(23):86-93,8.基金项目
国家科技支撑计划（2013BAF01B02）；国家自然科学基金资助项目（51369015）；甘肃省自然科学基金资助项目（2011GS04264）。 （）
