Abstract: For the axial fan and motor system of the commercial unit under high speed, abnormal noise were tested and analyzed, the frequency characteristics of the abnormal noise were initially determined; combined with the experimental and simulation analysis method, the structure and the flow field characteristics of the axial fan were analyzed, the main reason of the abnormal noise and it related improvement points were determined; based on these improved points of the flow field, we have completed the related CFD analysis and given the corresponding flow noise improvement methods, which is viewed from the ODS of the axial fan and the interference between the cavity of the flow field and the tip; according to the improved schemes, the improved axial fan and the related experimental verification were completed, the abnormal noise has been significantly improved.

Key words: Air conditioner, ODS, Axial fan, CFD, Flow noise