Design of Large-Scale, High-Efficient, Vertical Wind Turbine

Abstract

This paper presents the overall design of a 2 MW vertical-type wind turbine power generation system. Firstly, the performance of the jet-wheel turbo turbine was optimized by considering the design parameters such as the rotor inlet angle, the solidity, and the diameter-height ratio with the guide vanes fixed. The effects of the side guide vane and the opening area ratio upon the efficiency were tested. As the wind speed increases from 3m/s to 7m/s, the maximum power coefficient reached the limit value of about 0.6 based on the rotor area, which is much higher than those of ever-designed three-bladed horizontal turbines. The maximum power coefficients occurred at the tip speed ratio ranging between 0.6 and 0.7. Based on the performance of small prototype model, the large-scale wind turbine rotor was designed within the constraints of material cost, machining cost, structural safety at extreme conditions, and maintenance. Thus, the aspect ratio of the diameter-to-height and the hub-tip ratio were set as 0.8 and 0.0857, respectively. All sides of the rotor were almost opened to achieve a maximum efficiency with only possible blocking by the sprocket gear attached to the bottom of the rotor. To evaluate the structural safety of the turbine at extreme wind speeds over 25m/s lasting 10 minutes, the numerical simulations were performed to evaluate the pressure loadings on the blades and the guide vanes. According to the structural analysis based on the pressure loadings and its weight, the entire system is considered to be stable for the extreme and static loadings. The overall performance of the jet-wheel turbo wind-turbine system was analyzed to find the capacity factor for the wind characteristics of Gillim province in China by considering the gear box efficiency, the roller bearing losses, and the SCIG/DFIG generator efficiency.