School of Mechanical Engineering, Kyungpook National University, Daegu, 41566, Korea
This paper presents the numerical analysis of three types of magnesium-based, axial-flow automotive cooling fans. The numerical modeling is conducted for geometrically modified fan designs with and without bead structure. The effect of geometric modifications of the fan blades on the fan performances (P-Q curve), fan efficiency, and energy efficiency is investigated using unsteady Reynolds-Averaged Navier-Stokes (URANS) equations with the sliding mesh methodology. The baseline fan having no-beads is fabricated using 3D printing technology and tested to measure the flow velocity and volumetric flow rate which shows good agreement to the numerical results. Subsequently, fans with beads are further optimized to achieve a significant increase in fan performances. To investigate the fan vibrations, modal analysis is also carried out using magnesium-alloy AZ31 as the fan material. The modal analysis gives natural frequencies of all types of fans which are beyond the fan rotational frequency and seems satisfactory.