Numerical investigation of impeller trimming effect on performance of an axial flow fan

To study the performance variations of an axial fan after impeller trimming, numerical simulations are executed under the following conditions: trimming quantity of 5%, 10%, and 15% of blade height, with tip clearance changed and unchanged. The effects of trimming quantity and tip clearance on flow...

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Bibliographic Details
Published inEnergy (Oxford) Vol. 75; pp. 534 - 548
Main Authors Li, Chunxi, Li, Xinying, Li, Pengmin, Ye, Xuemin
Format Journal Article Conference Proceeding
LanguageEnglish
Published Kidlington Elsevier Ltd 01.10.2014
Elsevier
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Summary:To study the performance variations of an axial fan after impeller trimming, numerical simulations are executed under the following conditions: trimming quantity of 5%, 10%, and 15% of blade height, with tip clearance changed and unchanged. The effects of trimming quantity and tip clearance on flow field and performance of the axial fan are investigated, and formulae are presented for total pressure rise and flow rate ratio versus impeller diameter ratio and for operating points before and after impeller trimming. The simulated results show that the performance curves after impeller trimming tend to decline. Near the design flow rate, the performance of the fan with unchanged tip clearance is aerodynamically superior to that with changed tip clearance; the former deteriorates at a large flow rate. The margin of parameters provided by design units exceeding the actual operation requires the fan to normally operate to the left of the rated load, therefore, axial fans with tip clearance unchanged after impeller trimming have been found to maintain better performance. The equations, denoting total pressure rise ratio and flow rate ratio versus impeller diameter ratio are available to determine the trimming quantity according to actual requirements of operating points after impeller trimming. •Performances of the fan after impeller trimming are compared with original fan.•The effects of tip clearance changed and unchanged are examined.•The variations in flowing losses before and after impeller trimming are analysed.•The formulae of operating point before and after impeller trimming are presented.
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ISSN:0360-5442
DOI:10.1016/j.energy.2014.08.015