Investigation of aerodynamics characteristics of micro wind turbine with different flanged diffuser and blades

• Main Authors: Cheng-Wei Hung, 洪呈緯
• Other Authors: Tseng-Yuan Chen
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/50825496953292189758

碩士 === 淡江大學 === 航空太空工程學系碩士班 === 100 === Abstract: This thesis investigates the aerodynamic characteristics of micro, horizontal-axis wind turbine with different flanged diffusers and blades. First, a numerical study using FLUENT was conducted to investigate the flow field inside the flanged diffusers. A flanged diffuser with inlet diameter of 30 cm, length of 10 cm and diffusion angle of 30o was used for this purpose. Results show that the flow accelerates by 50% inside the flanged diffusers. Experimental study shows that a better power output can be achieved when installing the flanged diffuser inside a wind shield of 50 cm height, 20.5 and 46.5 cm top and bottom widths, respectively.The blades applied in this thesis are large-tip, non-twisted due to easily machined. The experimental studies were conducted in a wind tunnel system to obtain the relations between the power coefficient (CP) and tip speed ratio (TSR), and between the torque coefficient (CT) and TSR. Effects of the rotor position inside flanged diffuser, rotor solidity and blade number on rotor aerodynamic performance are investigated. The blade cross-section is NACA4415 airfoil. 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. Results show that larger power output is obtained when the rotor positioned approach the diffuser inlet. The larger the blade number is, the higher the power output is, but the difference is limited. In general, the 60%-rotor solidity achieves a better power output. Comparisons between the present and previous blades show that non-twisted, large-tip blades have better power and torque coefficients, and achieve the larger power output at lower rotor rotational speed. This result provides some important information in blade design of micro-wind turbines.