Optimization of Tip Clearance Patterns of Variable-pitch Axial Flow Fan

doi:10.16182/j.issn1004731x.joss.201810041

Abstract

Abstract: The performance of the axial fan can be improved by optimization of blade tip pattern effectively. For a variable pitch axial flow fan of OB-84 type, the performance of the fan with uniform tip clearance and non-uniform tip clearance are simulated by using Fluent. The impacts of tip patterns on leakage flow field and loss distribution in the tip clearance are examined. The results reveal that when average tip clearance keeps constant, the total pressure rise and efficiency of the fan with convergent tip clearance patterns are higher than those of uniform tip clearance, and the domain of higher efficiency is expanded. With the increase of convergent level, the improvement of performance tends to be appreciable. Convergent tip clearance changes the distribution of vorticity field, resulting in the reduction of leakage losses of blade tip and the promotion of work capability in the middle and upper part of blade. When the divergent tip clearance patterns are employed, the work capability of blade is declined, leading to slightly decreased fan performance compared to the uniform blade tip. The convergent tip clearance pattern is considered as a preferred mean to improve fan performance in practical applications.

Key words: axial flow fan, tip clearance patterns, aerodynamic performance, leakage flow, internal dynamics

CLC Number:

TH4
O355

Ye Xuemin, Cui Jianguang, Li Chunxi. Optimization of Tip Clearance Patterns of Variable-pitch Axial Flow Fan[J]. Journal of System Simulation, 2018, 30(10): 3939-3948.

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