Design based on a parametric analysis of a drag driven VAWT with a tower cowling

In order to improve the performance of vertical axis wind turbine (VAWT), this paper designs a new type of VAWT. It contains a tower cowling and a wind rotor. The tower cowling is actually a tower. The rotational axle of this new structure is mounted on the two sides of the tower, so this new type of wind turbine has a very good mechanical performance. To illuminate the influence of tower cowling, this paper chooses a variety of Savonius wind rotor to represent different kinds of VAWT. There is a cylindrical space used to place the wind rotor in the center of the tower cowling. There are eight baffles with circular distribution in the tower. Through adjusting wind direction, the tower cowling can make more wind forcing on the inner part of blades which produce positive torque, and prevent wind from forcing on outer part of blades which produce negative torque. Furthermore, the tower cowling can increase wind speed reaching the wind rotor, so the wind rotor can gather more energy and start more easily. To get the best performance of this new type of wind turbine, with the help of Fluent 6.3 software, this paper optimizes the main structural parameters that affect the power coefficient (CP) of this wind turbine. The vector and pressure around the wind turbine are compared when the wind rotor is with a cowing and without a tower cowling. Finally by comparing the value of CP and analyzing the influence tendency of the parameters, this paper obtains the optimal structural parameters and their influencing rule.