Study on Flow Fields and Noise Characteristics of a Small Axial Flow Fan Used in Narrow Space

Flow and noise characteristics measurements around a small axial flow fan for PC-cooling used in narrow spaces are executed. To simulate the flow field in narrow spaces, a flat plate is placed at a certain distance downstream of the fan outlet. The distance between the fan and the object, referred to as gap in this study, is varied to examine how the gap changes the flow behaviors and noise characteristics of the fan. By varying the gap, the blockage effect on the flow field and the associated noise level are investigated. The flow field at the location of trailing edge of the fan blade and edge of inlet measured using a three-dimensional laser Doppler velocimetry. As for fan noise, the tested fan is installed in an anechoic room, and the noise is measured simultaneous with 7 microphones located 150 mm surroundings of the fan inlet. The experimental results show that the flow field downstream of the axial flow fan and the fan noise change significantly in accordance with the spacing between the fan exit and the blockage plate.