Effect on Inlet Vent Porosity on Fan Characteristic Performance for Electronics Cooling

Critical fan performance metric such as characteristic output curves and maximum flow rates are affected by various environmental conditions where cooling fans are installed. This paper describes the relationship between the fan performance and configuration factors such as the flow inlet porosity of electronic enclosure, the flow obstacles which imitate high-density packages and narrow flow area configurations. We installed a test enclosure in front of a test fan and measured P-Q curves of the test fan, which were operated in the enclosure. The experiments, it was observed that the pressure difference was increased in the enclosure by the effects of a wall. We installed a perforated plate in front of the fan as an obstacle and investigated how this changed the P-Q curve. In general, addition of the perforated plate in front of the fan decreased the characteristic output of the fan. On the other hand, the flow rate by the fan supply was decreased by the existence of the narrow inlet or obstacles. When an opening area in front of a fan became smaller than double of the fan flow area, the flow rate was significantly decreased. In addition, it was observed that the maximum flow rate depended on the opening area ratio. Finally, a model for predicting flow rates decreases by the enclosure inlet and obstacles was proposed.