| Centrifugal fans have been widely utilized in many industrial areas involving agriculture,forestry,energy recycle,chemical industry,and so on.At present,most of the researchs on centrifugal fans focus on their performance under rated working conditions,and the actual operation is affected by the production load,process conditions and ventilation system.The fans often operate inefficiently under variable working conditions.To satisfy the needs of continuous changes in volume flow and pressure for industrial product,the inlet guide vane(IGV)will play more and more important role on all operation conditions.According to the key problem,this thesis focuses on an optimal impeller-guide vane matching relationship through the effective coordination of guide vane types and impeller blades.The effect of different guide vane optimization schemes on the performance of high specific speed centrifugal fan is studied and extensively analyzed.And we discuss the influence of impeller-guide vane matching relationship on structural characteristics of high specific speed centrifugal fans for efficiency enhancement.The influence of a high specific speed centrifugal fan charactcristics on performance on all operation condition is investigated.The impact of axial installation distance for IGV on the aerodynamic performance of a high specific speed centrifugal fan is propoesed.The major contributions of this thesis are presented below: The efficiency of the symmetrical airfoil guide vane with twist angle at the root and tail is the highest at various operating points at different guide vane openings.Compared with the origin fan,the impeller-guide vane matching relationship of the symmetrical airfoil guide vane and the airfoil blade of impeller made the centrifugal fan most efficient.The efficiency was increased by 1.55%,and the centrifuge fan operating stability is improved because of axial force decrease. |
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