| Summary: | 碩士 === 崑山科技大學 === 機械工程研究所 === 106 === This Thesis (Study) is aimed at improvement of performance of a VAWT (vertical axis wind turbine) in the area of dynamic blade pitching as opposed to fixed blade pitching. The area for performance improvement is directed towards the coefficient of power. Fortran theoretical data points (results) were studied in ANSYS Fluid Flow (CFX) code, the aim was to find the blade pitch setting from [β°=-10,-8,-6,-4,-2,0 ,+2,+4,+6,+8,+10] that provides the optimum torque at azimuthal angles in the rotation spectrum of a VAWT from 0 to 360 degrees with increments of 15 degrees. This study was performed using a single blade to save processing time as opposed to the three blades in a VAWT. This Thesis can be categorized into four parts, the first two parts are brief insight into VAWT configurations and performance analysis methods of VAWTS. The following part is references on previous research done by various authors in fixed blade pitching and dynamic blade pitching showing its promising effects on performance improvements in VAWTs. The final part is the definition of parameters, theoretical data and methodology of tests in ANSYS, also the results for test on TSRs. This Thesis is also a continuation of study done by (Kun-Cing Lee, 2017), where a new method is proposed as opposed to his method, which in his method showed overestimation of results and proven unreliable for the study. The new method proposed showed promising results agreeing with theoretical data by 0.31 % (percentage difference). The study done on TSR of 3 and 4 showed that; for both TSRs, the optimum blade pitch settings in the upwind region (0°≤θ≤180°) are negatives (β=-2°), (β=-4°) and ((β=0°) for TSR=3, while for TSR=4, the optimum blade setting in the upwind are (β=0°) and (β=-2°). In the downwind region (195°≤θ≤360°) the optimum blade pitch settings are positives, (β=+2°) and (β=+4°) for TSR=3, while for TSR=4 is (β=+2°). The blade pitch settings vary more in TSR=3 than in TSR=4. The study also shows that in dynamic blade pitching the performance improvement compared to fixed Blade pitching (β=0°) is 28.42 % for TSR=3, and in TSR=4 is much less with value in percentage difference of 1.19 %.
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