Improving the Power Output of Vertical Axis Wind Turbines Using an Optimized Grooved Blade Design

Vertical wind turbines are commonly used in urban environments due to their low manufacturing costs and simplicity, but they suffer from disadvantages such as a low power coefficient (Cp), difficulty in self-starting, and negative torque. The internal design and blade profile were modified in this study by first modifying the basic design to obtain a higher Cp through random parameter pair effects testing, from which the Combined H-Darrieus Rotor (CHDR) model was generated. Then, circular grooves were added to the lower surface of the blade (pressure surface), and the grooves were of different diameters and closely located with a fixed distance between them. After modifications, the Grooved H-Darrieus Rotor (GHDR) model was obtained. The results indicate that adding grooves to the CHDR blade design can improve the overall performance of the turbine as well as the aerodynamic performance. The results showed that increasing the groove diameter leads to an improvement in the Cp and torque C T up to a certain diameter after which the improvement stops. The best results were achieved with a groove diameter of 7 mm, where the turbine performed better at all tip speed ratios. The modified design showed a 54.7% improvement relative to the baseline model. When compared to the model without grooves, the grooved configuration achieved a 10.8% increase in the maximum Cp in the GHDR model.