0

Full Content is available to subscribers

Subscribe/Learn More  >

Active Tonal Noise Control for a Computer Cooling Fan

[+] Author Affiliations
J. Wang, L. Huang

Hong Kong Polytechnic University, Kowloon, Hong Kong

Paper No. FEDSM2005-77141, pp. 465-474; 10 pages
doi:10.1115/FEDSM2005-77141
From:
  • ASME 2005 Fluids Engineering Division Summer Meeting
  • Volume 1: Symposia, Parts A and B
  • Houston, Texas, USA, June 19–23, 2005
  • Conference Sponsors: Fluids Engineering Division
  • ISBN: 0-7918-4198-7 | eISBN: 0-7918-3760-2
  • Copyright © 2005 by ASME

abstract

The noise sources on a blade can be divided into a thrust force component along the rotating axis, and a drag component on the fan rotational plane. The radiated noise is a result of acoustic interference among all blades, and the two source components. For a sample fan with B = 7 blades, and S = 7 struts, the drag noise is expected to cancel themselves out. The result is a simple thrust dipole along the fan axis. When B = 7 and S = 4, however, the dominant noise is a rotating drag dipole. This paper demonstrates, experimentally, the global elimination of the blade passing frequency tones from the thrust dipole and the rotating drag dipole for the two sample fans, respectively, by using a simple open-loop, feedforward control scheme. The rig consists of a miniature electret microphone used as a rotation sensor, ordinary loudspeakers, and a bandpass filter with adjustable amplitude and phase delay. The electret microphone is installed flush with the inlet bellmouth of the fan. It picks up the fluctuating aerodynamic pressure caused by the passing rotor blades, and is shown to perform much better than a normal optical tachometer.

Copyright © 2005 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In