Numerical analysis of a small ducted wind turbine for performance improvement

In this study, Computational Fluid Dynamics simulations are carried out to assess the effect of duct geometry on power output and flow characteristics for a custom-designed wind turbine. The results show that the elevation of power output for a wind turbine is strongly reliant upon the shape of the duct. While before reaching a certain tip speed ratio, ducting would actually decrease the power output level. It is also argued that the velocity recovery index can also be considered dependent upon to the duct geometry. While the record power coefficient for the bare turbine is calculated to be 0.46, a power coefficient of 0.78 is shown to be reachable by adding a duct, which indicates an increase of approximately 70%. The near wake flow was analysed and a relation between the back-pressure level and the calculated power output was verified. The study also presents a framework for sizing the optimum duct.