| Summary: | 博士 === 國防大學理工學院 === 國防科學研究所 === 100 === The purpose of this study is to analyze, via CFD methods, L9 Taguchi orthogonal array, wind-tunnel experiments and 33 experiment design method, NACA 4-digital series blade-section for a small vertical-axis-wind-turbine (VAWT) operating under the wind speed of 4~12m/s (Reynolds number ranged from 5.3 104 to 9 105). In this dissertation, the database of aerodynamic parameters for VAWTs were established by using L9 Taguchi orthogonal array, CFD simulations and wind-tunnel experiments to select the better geometry parameters of a blade-section for VAWTs. Five shapes of the NACA 4-digital series blade-section, NACA6422, NACA6412, NACA6404, NACA0022 and NACA4412 were selected to study the wind turbine performance affected by the blade-section of different thickness, camber, and blade setting angle when operating at different wind speeds and with extra loading.
Three main topics are included in this dissertation. The first topic is to establish the database of aerodynamic parameters for NACA 4-digital series blade-section. Secondly, for improving the performance of the commercialized NACA4412 straight-bladed VAWTs, a new configuration of VAWT combined with outer NACA4412 and inner Savonius blades (hybrid VAWT system) is successfully fabricated and its performance is also obtained by CFD and experiments. Finally, based on the experimental results, NACA6422 blade-sectin is selected to set up a 100W VAWT and to compare with the performance of the same 100W VAWT with NACA4412 blades. All results of this study can be applied to the blades design for VAWTs with the output power of 1~3kW.
The major contributions of this dissertation are listed as follows:
In CFD simulations, conformal hybrid meshes and dynamic meshes were used successfully for flow pattern calculation and aerodynamic analysis for VAWTs. Comparing the CFD predictions of CP (Power Coefficient) with experimental results, the agreements were quite well.
In wind-tunnel experiments, the test model was a H-Rotor VAWT. A platform for output power test for small VAWT was successfully set up. Five shapes of the NACA 4-digital series blade-section used in VAWTs were tested and studied. Experimental results showed that a hybrid VAWT system (added with Savonius blades inside) has CP about 90％ higher than that of a VAWT with three NACA4412 blades and 3.5％ higher than that of a four NACA4412 blades VAWT.
This study not only produced a hybrid VAWT system, but also proposed that the cambered-thick blade of NACA6422 is more suitable for VAWT systems in the densely populated urban areas. The experimental results also provide valuable information to design and fabricate VAWTs.
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