An optimized airfoil geometry for vertical-axis wind turbine applications

ABSTRACT

In this work, a new airfoil shape optimized for vertical-axis wind turbine applications is proposed. Different airfoil shapes have been analyzed with JavaFoil, a panel method software. Then, the results from the analysis have been used to optimize the performance of the new airfoil shape. Afterward, Computational Fluid Dynamics (CFD) simulations of the proposed airfoil, UO-17-LDA, are run for different angles of attack to provide insight into the flow field and the mechanisms related to this increase in performance. The UO-17-LDA airfoil presents a high lift-to-drag ratio and a delayed stall angle with respect to the original FX-63-137 airfoil, making it suitable for vertical-axis wind turbine applications. This increase in performance has been verified by comparing two VAWT designs with the original and the proposed airfoil using a double-multiple streamtube model. Finally, the practicality of JavaFoil for the comparison of different airfoil geometries has been verified, as it is capable of obtaining results for a wide number of flow conditions in small computational times and with a user-friendly interface. Nevertheless, the results diverge from the actual solution for high angles of attack (beyond stall). Hence, the time and effort required to perform CFD simulations is justified to gain insight into the actual behavior of a particular airfoil, as well as to obtain a richer analysis of the flow field and the mechanisms related to the airfoil performance.