Effects of tip speed ratio on the performance of an H-Darriues wind turbine with NACA 4415 air foil

The effect of Tip speed ratio to the performance of an H-Darrieus Vertical Axis Wind Turbine (VAWT) is investigated numerically. The simulations are carried out for turbine blade made of NACA 4155 airfoil. A set of governing equations has been developed. In order to incorporate the turbulence effect, k−epsilon model is adopted. A commercial Computational Fluid Dynamic code is used to solve the problem. Four Tip speed ratios are tested, they are 0.5, 1.0, 1.5, and 2.0. The contour velocity in the computational domain was plotted and discussed. By using the average velocity of the wind leaving the turbine, power coefficient is estimated. The results show that at a chord length of 45 cm, the power coefficient for Tip speed ratio of 0.5, 1.0, 1.5, and 2.0 is 0.39, 0.51, 0.54, and 0.56, respectively. The conclusion here is Tip speed ratio strongly affects the power. Increasing the Tip speed ratio will increase the power. However, the effect of tip speed ratio is more effective at lower chord length.