Numerical Studies on the Effect of Cambered Airfoil Blades on Self-Starting of Vertical Axis Wind Turbine Part 2: NACA 0018 and NACA 63415

Abstract

NACA 0012 and NACA 4415 were discussed in Part 1 of the paper to study the capabilities of the airfoil blades by considering the effect of cambered airfoil blade on self-starting of vertical axis wind turbine. The numerical studies are carried out to identify self-starting capability of the airfoil using CFD analysis by studying the flow field over the vertical axis wind turbine blades. In this Part 2 paper, detailed numerical results of asymmetrical NACA 0018 and cambered airfoil NACA 63415 are presented. The lift force generated and the rotor torque induced varies with angle of attack. Based on the contours of static pressure and velocity distribution as well as based on the torque induced in the flow field over blade profiles, NACA 0018 is found to be better compared to cambered airfoil. Even though the lift force for cambered airfoils are higher, based on the rotor torque values, the wind turbine with asymmetrical airfoil blades NACA 0012 is better by 9.80% compared with NACA 4415 and 21.73% compared with NACA 63415. Self-starting issue can be addressed by proper selection of NACA blade profiles. By comparing the four airfoil blades in Part 1 and Part 2 of the papers, the asymmetrical NACA 0012 is found to be most suitable airfoil for self-starting the vertical axis wind turbine (VAWT).