Wind tunnel testing of scaled models of a newly developed Darrieus-style vertical axis wind turbine

摘要

Renewable sources of energy, needed because of the increasing price of fossil derivatives, global warming and energy market instabilities, have led to an increasing interest in wind energy. Among the different typologies, small scale vertical axis wind turbines (VAWT) have the greatest potential for off grid power generation at low wind speeds. In the present work, wind tunnel investigations about the performance of an innovative configuration of Darrieus-type vertical axis micro wind turbine has been made on scaled models specifically developed for small scale energy conversion at low wind speeds. The micro turbine under investigation consists of three pairs of airfoils. Each pair consists of a main and auxiliary airfoil with different chord lengths. A standard Darrieus configuration, consisting of three single airfoils, was also tested for comparison. The experiments were conducted in a closed circuit wind tunnel facility available at the industrial measurement laboratory (LaMI) of the University of Cassino and Lazio Meridionale. Measured data were analysed in terms of dimensionless power and torque coefficients. The auxiliary airfoil have demonstrated to give more torque at the lower wind speeds with respect to a standard Darrieus rotor, resulting in a better performance in terms of torque coefficient for all the wind speeds considered, while in terms of power coefficient, the standard Darrieus configuration has a slightly better performance for the highest wind speed analysed.