Design and Aerodynamic Performance Analyses of the Self-Starting H-Type Vawt Having J-Shaped Aerofoils Considering Various Design Parameters Using Cfd

Although the J-shaped aerofoil is a possible solution to enhance the torque generation at the low tip speed ratios, the effect of the J-shaped aerofoil on the overall and the dynamic start-up performances of the H-type VAWT has not been extensively studied. Therefore, for the first time, the present study is aimed at exploring the impact of the J-shaped aerofoil with different values of opening ratio on overall and dynamic start-up performance of the H-type VAWT considering different design parameters. The results show that a dynamic start-up model is needed to fully examine the self-starting capability of the J-shaped aerofoil instead of using calculated torque/power coefficients at the constant tip speed ratios. In addition, while the opening located at the inner surface of the aerofoil does not bring any benefit, the turbine self-starting ability increases with the increase in the opening ratio. Furthermore, there is a noticeable enhancement in the starting ability when the thicker NACA0018 aerofoil is employed, and the reversed version of the cambered aerofoils demonstrates a better self-starting capability compared to their original profiles. Additionally, the turbine with the J-shaped aerofoil having a slightly positive pitch angle (β=2°) has been found to have a better self-starting ability