An investigation of the effect of uneven blade spacing on the tonal noise generated by a mixed flow fan

Ludovic Desvard , Jeremy Hurault , Muhammad Affendi Bin , Mohamed Zamzam , Ash Symes

New Zealand Acoustics, 27(3), pp.23- 31 . (2014).

The current study investigates the flow performance and sound quality for a standard and an alternative compressor design for use in a Dyson desk fan. The alternative compressor has an uneven blade spacing to spread the associated energy of a single blade passing frequency to several frequencies in order to improve sound quality. The flow performance and acoustic signature for the two designs are compared both as a standalone compressor and installed in product. A dedicated sound preference model was developed to objectively evaluate the acoustic signature of both designs. This methodology can be used to help optimise compressor design in terms of user preference.