CFD-Based J-Shaped Blade Design Improvement for Vertical Axis Wind Turbines

Abstract

The need for an increase in energy harvesting has led to novel ideas and designs to extract more power from wind. One innovative solution is through the use of J-shaped blades for Darrieus vertical axis wind turbines (VAWTs), which is based on the removal of a portion of a conventional blade, either on the pressure or suction side. Although improvements in the self-starting capabilities of VAWTs have been reported when using such blades, the literature only studied hollow blades, showing a hair-like structure. This work numerically investigates six different J-shaped designs. A turbine comprising NACA0015-based blades forms the base case and is used to evaluate the 2D numerical models. Results show that blades with an external cut systematically outperform those designed with an internal cut. In addition, all proposed cut-based designs are shown to improve the starting torque of the turbine, reaching a 135% increase compared to the base model.