Abstract
In recent years a compact axial flow fan has been used for cooling of electronic instrument because of its large flow rate. The improvement of fan efficiency and the noise reduction are required considerably. However the electronic parts located upstream fan generate the turbulence of inlet flow, whose effects on fan characteristic and noise are not clarified. In this paper the effects of turbulence of inlet flow generated by grid on the fan characteristics and fan noise are investigated. The results are that in the case of same turbulence intensity the turbulence having large vortex causes larger fan noise than the turbulence having small vortex, and that the fan efficiency at the large flow rate region is improved with the increase of turbulence intensity.
