Numerical performance assessment of a novel Darrieus-style VAWT with auxiliary straight blades

Abstract

Domestic Vertical Axis Wind Turbines (VAWT) are able to operate also when the wind speed is low and can be installed in the open spaces of housing areas. The Darrieus turbine is the most promising since it is characterized by higher efficiency, even if for applications at higher wind speeds with respect to Savonius VAWTs. Several researchers try to optimize the aerodynamics of the Darrieus rotors, allowing wind turbines to start rotation even in the presence of low wind speeds. In this paper the authors propose a numerical investigation of the flow field around a 1:4 scaled model of a pair of blades installed on an innovative Darrieus-type VAWT. A Reynolds Averaged Navier-Stokes-based CFD model was validated on the basis of the wind tunnel data, and the scaled turbine performance was analysed by numerically evaluating the effect of different geometric configurations and rotation angles on the turbine torque coefficients. The results of the simulations confirmed the capabilities of the proposed configuration to give valuable performance even for low wind speeds.