The Noise Prediction of Automotive Axial Fan with Different Blade Sweep Angle using Unsteady CFD Analysis

A1 - CEVAS Project (HVAC of cars)

This study is carried out for automotive axial fan with the three types of swept blade: forward, backward and straight, using three dimensional unsteady CFD analysis. Acoustic analogy by Ffowcs-Williams-Hawkings is used to predict the sound propagation in the far-field. Unsteady RANS and SST turbulence models are used for CFD analysis. The predicted results are validated with the following experiments. The three fans with different sweep angles show quite different performance and noise levels. Especially the overall noise of the forward swept fan shows 2 to 3 dB which is lower than the straight blade and backward swept fans’ at the same flow rate. The main purpose of this study is to explain what causes the differences in performance and noise level in terms of flow characteristics, and how the sweep angle of blade affects the overall fan noise level. The corresponding setup in CFD analysis and experiment include just cooling fan and shroud without heat exchangers