軸流ファンの流動特性に及ぼす障害物の影響

抄録

The system environments of the axial flow fan are various. The axial flow fans are often used under unsuitable operating condition. Especially, the cases where the obstacles are distributed in upstream of the fan to downsize are increasing, in recent high density design of equipment. An attempt is made to clarify the influence of the obstacle on the flow characteristics of axial-flow fans. In this study, a blockage disk is installed upstream of a test fan which is a typical cooling axial-flow fan. Blockage disks with various diameters are set up. The performance curves of axial-flow fan with blockage disks are measured. In addition, flow instabilities with a cell structure are demonstrated on typical condition. The main objects of the present study are : to evaluate the performance degradation when obstacles are installed in upstream of the test fan, to elucidate causes of positive slope for the performance characteristics curves and reverse flow, to clarify the generation mechanism of flow instabilities when the blockage disks which are larger than diameter of the test fan are installed.