This paper describes the effects of frame and inlet sizes of an electronic casing on the cooling fan performance. The performance of air-cooling fans is defined by their P-Q (Static pressure-Flow rate) characteristics. Recent studies report that P-Q characteristics of cooling fans depend considerably on their operational environments. In previous study, we evaluated P-Q characteristics including effects of frame by defining static pressure as pressure difference between chamber and air pressure. But usually, static pressure means pressure difference between backward and forward of fan. So in this study, we measured flow rate and pressure difference between the front and the rear and explored effects of frame, especially effects from area of inlet sizes. From experimental results, it was found that the fan P-Q characteristics were changed by frame, and flow rate were affected strongly by inlet sizes.
