Advanced blade profiles for improved efficiency in Savonius wind turbines: the aeroleaf case study

Area of Science:

• Renewable Energy Engineering
• Aerodynamics
• Turbine Technology

Background:

• The Aeroleaf, a compact Savonius-based vertical-axis wind turbine (VAWT), is suitable for urban environments but suffers from low aerodynamic efficiency.
• Its baseline performance was compared to a conventional Savonius wind turbine (CSWT) under identical conditions (Re ≈ 1.7 × 10⁵, U = 7 m/s).

Purpose of the Study:

• To evaluate the aerodynamic performance limitations of the baseline Aeroleaf.
• To investigate the impact of integrating four optimized blade profiles (scooplet, S-shaped, Roy, elliptical) on the Aeroleaf's efficiency and startup torque.
• To determine the most effective blade profile for improving small-scale urban wind energy generation.

Main Methods:

• Comparative analysis of the baseline Aeroleaf and CSWT under specific Reynolds number and wind speed conditions.
• Computational Fluid Dynamics (CFD) simulations were employed to assess the performance of the Aeroleaf with modified blade profiles.
• Static and dynamic torque analyses were conducted to evaluate startup potential and operational torque.

Main Results:

• The baseline Aeroleaf achieved a peak power coefficient (Cp) of 0.107 at a tip speed ratio (TSR) of 0.5, with a static torque of 0.301 N·m at 90°.
• The scooplet blade profile demonstrated the most significant improvement, reaching a Cp of 0.180 at TSR 0.6 and a static torque of 0.443 N·m, representing substantial gains over the baseline.
• Other profiles (S-shaped, Roy, elliptical) also showed performance enhancements, but to a lesser extent than the scooplet.

Conclusions:

• Optimized blade profiles, particularly the scooplet, effectively address the aerodynamic limitations of the Aeroleaf.
• The scooplet profile significantly enhances both the peak efficiency and startup torque of the VAWT.
• These improvements position the Aeroleaf with optimized blades as a more reliable and efficient solution for small-scale urban wind energy applications.