Prediction of Aerodynamic Noise in Axial Fan Using Serration Edge Blades

Abstract

This paper presents the numerical analysis on the aerodynamic flows and noise of serrated blades axial fan. Unsteady flow and noise analysis were simulated with an embedded SST k-ω turbulence model and Ffowcs-Williams Hawking's equation. Nine modified axial fan blades models are evaluated and compared with the original model. It was confirmed that the original models concord with the experimental results of the performance curve. The effectiveness of serration is investigated with different values and ratios of amplitude (h) as well as spanwise wavelength (λ). The results indicated that a large reverse flow vortex obtained in the original model compared to serrated models. Remarkably, the serration edges showed an efficient noise reduction achieved by models λ/h=0.25 and λ/h=1, which reduced the noise by 14 dB and 4.2 dB, respectively. Besides a noise reduction up to 11.4 dB was achieved using different values of λ and h at the same serration ratio.