Two methods for reducing the high frequency noise radiated by small axial fans which constitute the cooling systems of electronic equipment are studied. The first method focuses on modifying the characteristics of the tip gap flow to reduce the energy in the tip vortex by inhibiting flow through the gap. The method requires the addition of flanges to the blade tips to equalize the pressure differential across the tips and reduce the flow through the tip gap. Above 2.5 kHz, the decrease in the tip gap results in a broadband reduction of as much as 7 dB. The second technique involves adding fabric strips to the trailing edges of the fan blades. The first and second techniques combined provide 5-10 dB noise reduction above 1.5-2 kHz.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings - National Conference on Noise Control Engineering|
|State||Published - 1996|
All Science Journal Classification (ASJC) codes
- Acoustics and Ultrasonics