Geometric Modifications for Noise Mitigation in Axially Rotating Fan Blades

Abstract This study explores the effect of laminar and turbulent boundary layers, as well as boundary layer separation, on noise generation from an axial rotating blade of a ducted fan. Quieter fans provide significant advantages in terms of regulatory compliance, comfort, efficiency, safety, health, and sustainability across industries like aviation and HVAC. Additionally, reducing noise pollution and its impact on the ecosystem, along with minimizing vibrations and wear, can extend the lifespan of components. This investigation was conducted using a case study of a seven-blade axial fan designed by CF Turbo software. The study examines the impact of reducing the chord length from 7.5 cm at the root to 3.56 cm at the tip on noise generation at a constant rpm. A comparative analysis was also carried out between the sound generated by the original and modified blades, revealing a noticeable 28% reduction in the peak overall sound power level.