- 學位論文
具外罩水平及垂直軸風力發電機特性探討
Performance Studies of Horizontal-axis and Vertical-axis Wind Turbines with Shrouds
摘要
本研究可分為兩部分，第一部分為水平軸風力發電機搭配擴散外罩，探討不同的葉片及擴散外罩擴散角度的空氣動力特性，並與發電機匹配。本研究以不同螺距角度與不同的葉片葉根與葉尖比例Cr/Ct作比較。結果顯示，螺距角度為30度以及Cr/Ct為0.3時，大幅提升功率和扭矩輸出。比較擴散外罩不同擴散角度後，顯示擴散角度30度之擴散外罩有具有較佳效果。本研究將葉片與發電機做匹配，證實能帶動扭矩小的發電機並發電。 第二部分探討應用於阻力型垂直軸風力發電機之漩渦流集風罩，本研究利用集風罩使氣流於集風罩內部產生漩渦流原理，搭配阻力型葉片，使阻力型轉子轉動至任何位置時，皆能受到空氣正向推力的作用。數值模擬顯示集風罩內部確實產生漩渦流結構。本研究比較導流板不同片數、長度及風向角度後，實驗結果顯示，6片導流板、長度24公分之漩渦流集風罩有較佳特性，搭配集風罩後，直徑只增加80%，但功率輸出可達到7~10倍。轉子啟動風速也降至1m/s左右。
並列摘要
The thesis studies of horizontal-axis and vertical-axis wind turbines with shrouds, which is divided into two parts. Part 1 investigates the aerodynamic characteristics of horizontal-axis wind turbine (HAWT) with different flanged diffusers and blades. Results show that larger power output is obtained when the pitch angle of the blades is fixed at 30°, and the chord length ratio between the blade root and tip is fixed at 0.3. Flanged diffuser diffusion angle of 30° have larger power output. Part 2 investigate a vortical stator assembly (VSA) which was developed to improve the rotor performance, surrounding a drag-type, vertical-axis wind turbine (VAWT). The design was created to generate vortical flow inside the VSA; thus, the rotor blades always generate positive torque because they rotate in the same direction as the vortical flow. A numerical simulation was performed to verify the flow structures around and inside the VSAs. The experimental results indicated that VSAs can substantially augment the rotor performance, depending on the number and length of the guide vanes used. The augmentation ratios of the rotor power outputs with the VSA were between 7 and 10 under the investigated wind speeds 6 m/s, and wind directions between 0° and 50°. The diameter of the rotor integrated VSA increased by less than 80%. Results also show that the rotor starting speed was reduced to approximately 1 m/s.