Effect of blade number on performance of drag type vertical axis wind turbine

The effect of blade number on performance of drag type vertical axis wind turbine (VAWT) is studied by Ansys numerical simulation, it involves 3-blade, 5-blade and 6-blade VAWTs. The optimized width of blade for each VAWT at maximum power efficiency is obtained, and simulation for the wind turbine with different number of blade is conducted for the VAWTs with turbine radius of 2 m at the inlet wind speed 8 m/s. By simulations, it gets the evolution curve of torque with respect to time, and the cyclical characteristics for these wind turbines. The results show that the maximum power efficiency and the stability of the wind turbine increase with the number of blade of the wind turbine, however the optimal d/D decreases with the number of blade of the wind turbine. The maximum power efficiencies are 20.44, 24.30 and 26.82% for 3-blade, 5-blade and 6-blade wind turbines, and the correspondingly optimal d/D are 0.66, 0.40 and 0.35, respectively. While the optimal rotational rate of turbine decreases with blade number.