Design, fabrication, and testing of a savonius wind turbine with helical blades

Abstract

This study focused on the design, fabrication, and performance evaluation of a helical-bladed Savonius vertical axis wind turbine (VAWT) intended for small-scale and decentralized energy applications. To improve upon the limitations of conventional Savonius turbines—specifically low efficiency and poor self-starting performance—a 90-degree blade twist, an overlap ratio of 0.08, and circular end plates with a 1.1 diameter ratio were incorporated into the design. The turbine components were fabricated using polylactic acid (PLA) via 3D printing, then reinforced with epoxy resin for improved strength and durability. This approach enabled rapid, low-cost prototyping of complex blade geometries. Performance testing was conducted in a wind tunnel across wind speeds ranging from 6 to 10 m/s, using a rope brake system to simulate mechanical loading. Key performance metrics—including rotational speed, torque, tip speed ratio (TSR), and power coefficient (Cp)—were measured. The turbine achieved its highest efficiency at a corrected wind speed of 3.0 m/s (9 m/s tunnel speed), reaching a peak Cp of 0.232 at a TSR of 1.798. This exceeded the Cp value of 0.21 reported in prior studies, despite operating at a lower wind speed. The results demonstrate the effectiveness of helical blade modifications and additive manufacturing in enhancing the performance of VAWTs. The study highlights the turbine’s suitability for low-wind and off-grid environments, contributing to the advancement of accessible, sustainable wind energy technologies.