On the basis of a semi-empirical model, large Gurney flaps of 10%, 20%, and 30% of the fan blade chord length were tested in a specially designed ventilation fan facility. At the highest volumetric flowrates tested, the flapped blades all produced higher pressures than the baseline nonflapped case. When proper accounting was made of fan rotational speed, all flapped blades produced consistently higher dimensionless pressures, with the 30% flap producing the highest pressures at large volumetric flowrates. Based on the assumption that sound power varies with the sixth power of fan rotation speed, it was shown that the sound pressure level could be reduced by nearly 4 dB. All flapped configurations produced higher mechanical efficiency than the baseline case but the mass of the flap relative to that of the blade emerged as an important parameter. A 10% flap, whose mass was negligible relative to the blade, produced the largest increase of 18% in static efficiency. Further research will focus on testing the flaps over the entire operational range, as well as on redesigning stiffer and lighter Gurney flaps. The introduction of three-dimensionality such as spanwise spaced holes, slits, or serrations that have previously been used to reduce airfoil drag will also be considered.
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February 2011
Research Papers
Application of Large Gurney Flaps on Low Reynolds Number Fan Blades
David Greenblatt
David Greenblatt
Faculty of Mechanical Engineering,
Technion – Israel Institute of Technology
, Haifa 32000, Israel
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David Greenblatt
Faculty of Mechanical Engineering,
Technion – Israel Institute of Technology
, Haifa 32000, IsraelJ. Fluids Eng. Feb 2011, 133(2): 021102 (8 pages)
Published Online: February 4, 2011
Article history
Received:
June 6, 2010
Revised:
December 19, 2010
Online:
February 4, 2011
Published:
February 4, 2011
Citation
Greenblatt, D. (February 4, 2011). "Application of Large Gurney Flaps on Low Reynolds Number Fan Blades." ASME. J. Fluids Eng. February 2011; 133(2): 021102. https://doi.org/10.1115/1.4003301
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