Self-Starting Capability Improvement of Single and Dual Hybrid Darrieus-Savonius VAWTs, Incorporating a Gear Mechanism

The substantial increase in greenhouse gas emissions has catalyzed the growth of renewable energy sources. In this context, vertical axis wind turbines (VAWTs) have gained significant traction due to their numerous advantages. Notably, Darrieus VAWTs have demonstrated acceptable efficiency; however, their reliance on initial torque and challenges associated with self-starting capabilities prompted advancements in hybrid Darrieus-Savonius VAWTs. This configuration has primarily proven effective in enhancing efficiency within a low-tip speed ratio (TSR) range. However, hybrid rotors tend to experience performance degradation in high-TSR ranges. To address the performance decline observed in the high-TSR range, this study proposes an innovative solution by developing a dual-shaft hybrid rotor. This design functions as a control mechanism to prevent the angular velocity of the inner Savonius rotor from exceeding a specified threshold. For the first time, this design integrates Darrieus and Savonius rotors on a common shaft, then with two distinct rotors mounted on separate shafts. These shafts are connected through a gearless control mechanism that regulates the angular velocity of the Savonius rotor, ensuring it operates below an angular velocity of ۱۹.۷۹ rad/s. The findings suggest that both single and dual shaft configurations can improve rotor power coefficient  by up to ۷۲% and ۹۰%, respectively, in comparison to conventional rotors at a TSR of ۱.۴

کلیدواژه ها:

Self-starting capability ، Single-shaft hybrid Darrieus-Savonius VAWT ، Dual-shafthybrid Darrieus-Savonius VAWT ، Gear mechanism ، Vorticity field