| Summary: | 碩士 === 國立臺灣海洋大學 === 輪機工程學系 === 103 === This study aims to improve the efficiency of a drag-driven type of Vertical Axis Wind Turbine (VAWT) by designing an innovation blade geometry. The main methods adopted are Taguchi Methods of Robust Design for designing
and ANSYS-Fluent simulation software for experimental analysis.
Firstly, for the upwind front side of the blade, in accordance with factorial design method identified total four control factors：(1) the upper and lower sides of blade geometry with enclosure or not, (2) hollow depth on
the flat surface of front side, (3) size of ellipse major radius to semi-oval surface at the back side, and (4) winglet height at upper and lower sides of blade geometry. The factor of body enclosure at the upper and lower sides
of blade geometry has only two levels, while the other three factors will have three different sizes of three levels. Then, using Taguchi method of orthogonal arrays, getting nine out of fifty-four combinations for simulation.
Those nine combinations are simulated for total forces on the blade by using ANSYS-Fluent software under the same parameters with wind speed of five meters per second (5 m/s).
Then, in according to one of characteristics of Taguchi Methods, thelarger-the-better, derived total force value of nine simulations are calculated into the signal-to-noise (S/N) ratio. Through cross-analyze those nine sets of S/N ratio, the best level and the worst level of individual factor has derived. The innovation blade geometry, which is the combination of four factors with the best level, is simulated and verified. Meanwhile, the upwind semi-oval surface at back side of the innovation blade geometry in
different angle are simulated as well. This is to verify that if the innovation blade geometry does create some lift force.
Compare to blades with other geometry, this optimized innovative blade geometry not only captures more drag force on the upwind flat surface of front side, but also generates certain lift force on semi-oval surface at the
back side. The test method of this study will help to improve the blade efficiency of a vertical wind turbine and can be a design references for the new vertical wind turbine .
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