Abstract:Based on the SST k-ω turbulence model and vortex intensity method, the flow through the impeller tip and tip leakage vortex trajectory in a model axial-flow pump were simulated numerically. The influence of operational condition and tip clearance size on the trajectory was analyzed. It is shown that the starting point of leakage vortex core moves to the middle portion of blade from the blade leading edge gradually with increasing flow rate. The relative flow direction in the impeller passage is deflected and the trajectory of tip leakage vortex is altered accordingly under the entrainment induced by the primary flow with increasing flow rate as well. Note that the slope of the vortex core trajectory also gets enlarged by the primary flow. The rollup of leakage vortex is enhanced and the affected region is expanded, the starting point of the vortex also moves from the leading edge to the trailing edge, and the static pressure in the vortex core is decreased gradually, causing a risk of cavitation with increasing tip clearance size. A positive head curve appears at around 0.9 times the design flow rate under a tip clearance as large as 1.5 mm, suggesting the tip leakage vortex can influence the instability of head curve significantly.
施卫东, 邵佩佩, 张德胜, 吴苏青, 李通通. 轴流泵运行工况和叶顶间隙对叶顶泄漏涡轨迹的影响[J]. 排灌机械工程学报, 2014, 32(5): 373-377.
Shi Weidong, Shao Peipei, Zhang Desheng, Wu Suqing, Li Tongtong. Influence of operational condition and tip clearance size on trajectory of tip leakage vortex. Journal of Drainage and Irrigation Machinery Engin, 2014, 32(5): 373-377.
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