A hybrid analytical/experimental model for evaluation of the aerodynamic noise in fans

This paper presents all procedures used to obtain a reliable analytical model for the evaluation of the aerodynamic noise in fans used for cooling electrical motors. The final result is a mathematical model with parameters adjusted with both experimental data and computational fluid dynamics (CFD) analysis. In the validation of the proposed model, 135 experimental evaluations of noise level were done on different fans and it was verified that about 70% of the obtained results showed difference of ±1.5 dB in relation to the predicted by the new model, and 93% of the results showed difference of ±2.5 dB. It is important to emphasize that this difference is small when compared with results obtained by other existing methods. Besides, it is also shown in this paper a technique for optimization of fan rotors with respect to aerodynamic noise level.