Feature extraction of flow and acoustic fields for identification of noise sources and improvement of performance of small axial fans

Abstract

A detailed understanding of the characteristics of the flow field around small axial fans is essential to improve the performance and suppress aerodynamic noise of the fans. The feature extraction of the flow and acoustic fields around the fans enable us to obtain further understanding of them. In this study, the proper orthogonal decomposition (POD) and the dynamic mod decomposition (DMD) was applied for the high-resolution numerical data of the small axial fan. As a result, it was found that the waves were emitted from the root of the impellers and impeller, boss and the tip of the impeller or the gap between the impeller and the casing. Therefore, the aerodynamic noise source could be the tip, root of the impellers, and/or the gap between the impeller and the casing.