Abstract: In this paper, the numerical simulation method is used to investigate the even-spaced and uneven-spaced automotive cooling fans. The relationship between blade force and uneven-spaced blade distribution angle is analyzed through blade striping treatment, and the model between blade force and blade phase angle of uneven-spaced fan is established. Based on the characteristics of uneven-spaced fan blade force, a noise prediction method for uneven-spaced fan is proposed by using Lowson point force model, and a peak noise prediction model for low-speed non-uniformly distributed fan based on fan blade force model is established. The prediction model is verified by comparing with the prediction results of Lowson model based on computational fluid dynamics (CFD), experimental data and other uneven-spaced fan blade noise prediction models.

Key words: uneven-spaced blade; tonal noise; blade force characteristic; noise prediction