Literature Survey

The literature shows extensive research on improving fan efficiency and reducing aerodynamic noise across various fan types, including propeller, centrifugal, and axial flow fans. Propeller fans are simple and suited for low-resistance applications, centrifugal fans achieve higher pressures with backward-inclined blades offering good efficiency, while axial fans deliver high airflow but generate significant noise due to high tip speeds. Key parameters influencing performance include blade angle, tip speed, efficiency curves, and modern control techniques.

Standards such as the Electric Ceiling Type Fans Specification 2019 provide performance and energy-efficiency guidelines. Several studies demonstrate that CFD is effective for analysing airflow, with accuracy up to 91% compared to experiments. Research on automotive and industrial fans highlights major noise sources near blade tips and leading edges, guiding noise-reduction strategies.

Biomimetic studies, inspired by owl wings and other natural structures, show that serrations, surface textures, and feather-like edges can reduce turbulence and noise while maintaining aerodynamic performance. Experimental work reports noise reductions of 3–5 dB through optimised blade geometry. Additional studies on specialised blades—such as NACA air foil fans, hidden ceiling fans, and sycamore-seed-inspired blades—further show improved airflow distribution.

However, most research examines single biomimetic features in isolation. There is limited investigation into combining serrations, perforations, and tilted edges for domestic ceiling fans, and manufacturability assessments are often lacking. The present project addresses these gaps through integrated CFD–acoustic modelling and practical design evaluation.