ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

2aNS5. Effects of installation for computer cooling fans.

Jacklyn D. Bezemek

Luc Mongeau

Dept. of Mech. Eng., Purdue Univ., 1077 Herrick Lab., W. Lafayette, IN 47907

The aerodynamic performance and the noise emissions of computer cooling fans are influenced by the design of the computer enclosure and its internal components. Moreover, the coupling between the spatially distributed source and the acoustic response of the system hampers the use of most linear electroacoustic source filter models. Employing a method derived from acoustic similarity laws [Neise and Barsikow, ``Acoustic Similarity Laws for Fans,'' Trans. ASME 104 (May 1982)], the installation effects of three small axial cooling fans mounted in various computer-power supply assemblies have been determined by combining measurements in situ and standardized fan sound power measurements. It was found that flow performance may be reduced, additional sound may be generated due to inflow inhomogeneities, and the fan itself may affect the fundamental Helmholtz resonance of the computer and power supply cavities.