Abstract: The rear guide vane is a critical component influencing the aerodynamic and acoustic performance of mixed-flow fans. Inspired by owl wing morphology, the thickness distribution from a long-eared owl wing at the 40% spanwise section and applied it to biomimetic guide vane blades, using the prototype vanes' mean camber line as the baseline. Experimental measurements under identical airflow conditions showed that the fan equipped with biomimetic vanes achieved a 1.4% efficiency improvement and a 0.8 dB noise reduction compared to the prototype. Numerical simulations revealed no significant low-velocity zone near the biomimetic vane trailing edge, with a more uniform flow distribution and effective suppression of flow separation and vortex shedding. The results demonstrated enhanced matching between the impeller and guide vane, significantly reducing impeller outlet flow impact on the vane leading edge. Furthermore, noise analysis confirmed reductions in both broadband and discrete noise within the mid-to-low frequency range, achieving dual objectives of higher efficiency and lower noise emission.

Key words: Mixed flow fan, Rear guide vane, Bionic design, Aerodynamic performance, Noise