Numerical investigation and aerodynamic simulation of Darrieus H-rotor wind turbine at low Reynolds numbers
Hossein Seifi Davari, Shahriar Kouravand, Mohsen Seify Davari, Zahra Kamalnejad
Abstract
In order to select an airfoil suitable for the wind tunnel testing on a three-bladed Darrieus H-rotor wind turbine, several symmetrical National Advisory Committee for Aeronautics (NACA) 4-digit, NACA 4-digit, NACA 5-digit, and Selig airfoils with chord Reynolds numbers (Rec) of 17,890, 35,780, and 53,670 were studied. To achieve higher aerodynamic performance at Re of 17,890 to 53,670, the NACA0015 airfoil was selected. The lift coefficient (Rec) of the NACA0015 airfoil after shape modification has reached values of 0.788 to 0.936 at Re of 35,780 and 0.925 to 1.027 at Re of 53,670 with the same stall angle (AoAstall) in both investigated Re, according to the results of modifying the airfoil’s thickness and chord. Additionally, the NACA0015 modified airfoil’s maximum lift-to-drag ratio coefficient (CL/CD) increased by 34.01% and 17.94% at Re of 35780 and 53,670, respectively. Likewise, the analysis showed that the NACA0015 modified airfoil’s maximum performance coefficient (CP) increased from 0.129, 0.242, 0.285, 0.308, and 0.33 to 0.152, 0.272, 0.307, 0.331, and 0.354 at Re of 100,000, 150000, 200000, 250000, and 300,000, respectively. As well as the findings demonstrated that the XFOIL code provides the most accurate overall prediction results at low Re.