Performance analysis of a modified Archimedes spiral wind turbine having winglet on blade

Small-scale wind energy systems show growing potential for urban applications, yet face challenges in harvesting energy from low-speed urban wind environments. The Archimedes spiral wind turbine (ASWT) is an innovative design featuring a horizontal axis turbine, which has shown potential for localized energy harvesting in urban environments, but it exhibits poor efficiency. This study proposes a winglet-enhanced ASWT configuration and investigates the aerodynamic effects of winglet geometry parameters through computational fluid dynamics (CFD). Key findings demonstrate: (1) Winglet angle dominates performance optimization, with 90° serving as a critical threshold, angles exceeding 90° create an end-plate effect that suppresses tip vortices, reduces induced drag, and enhances lift generation, thereby improving power coefficient (CP). Conversely, angles below 90° exacerbate flow separation and tip drag. (2) Winglet length exerts secondary influence, showing progressive CP enhancement at angles ≥90° through pressure redistribution and velocity gradient intensification. Flow analysis reveals winglets with 135° angle and 6–7 % blade length gains excellent efficiency (achieving 13.4 % peak CP improvement over original turbine) without inducing high tip speed ratio performance penalties observed in 150° designs. This research offers important perspectives on the design and enhancement of ASWTs for use in urban settings.