Novel Induction Blade Design for Horizontal Axis Wind Turbines to Improve Starting Phase: CFD and Testing Analysis

This article introduces a novel Induction Blade (IB) prototype modeled by Blade Element Momentum (BEM) theory, which develops higher torque during the starting phase for Horizontal Axis Wind Turbines (HAWT), especially for micro-turbines. The IB is composed of two parallel blades joined at their tips and roots, forming a distinctive hole in the space between the blades that generates a Venturi effect as air passes through. This phenomenon in the IB hole together with the extra lift generated by the area of the second blade produce extra valuable torque during the starting phase. We used Computational Fluid Dynamics (CFD) analysis to evaluate the aerodynamic properties of this design compared with a traditional blade design of the same radius. The IB and traditional prototypes were built (50W, diameter 0.62m, λ=9 and at speed rated 8m/s) by additive manufacturing in a 3D printer and their aerodynamic behaviors tested in a small wind tunnel (square section 0.7m x 0.7m). Our results using CFD analysis show that this novel IB produces up to 65% extra torque without losing output power for low wind velocity (5-8 m/s). IMPI (Mexican Institute of Industrial Protection) protects this prototype shape.