| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 102 === This article is focused on developing the twin-rotor vertical axis windmill to capture the so-called secondary wind energy and performing its working efficiency measurements using LabVIEW program. Structurally, the inner and outer rotors are separated by twin-rotor mechanism so that the two rotors can be operated independently. In process, the inner and outer rotors were built in drag-type and lift-type blades respectively. The input wind energy can first be captured by the outer turbine and the inner turbine will capture the rest of wind energy which is also called the secondary wind energy. In this work, the twin-rotor vertical axis windmill can be distinguished from three generations in mechanical design. The first generation is focused on developing the twin-rotor mechanism idea and choosing the turbine blades type. The second one is to adjust the mechanism so that inner and outer turbines can be operated independently. The third generation concentrates on blades design to increase the working efficiency. Moreover, this work also used encoders and LabVIEW program to monitor the relevant information automatically, such as RPM, TSR and working efficiency of twin-rotor vertical axis windmill.
The results show that modified two-steps Savonius rotor has the best working efficiency of 19.5% at TSR = 1.05. For the outer turbine of semicircular drag-type with different number of Clark-Y blades, the results show that the outer turbine with three Clark-Y blades has working efficiency of 6.5% at TSR = 1.13. Moreover, this work used two and three outer blades to combine with the inner turbine as the twin-rotor vertical axis windmill for working efficiency measurements. The results show that when the inner and outer turbines turn contrarily with any number of outer blades will received benefit for the inner turbine and disadvantage for the outer turbine, when the inner and outer turbines turn in same direction also with any number of outer blades will received the opposite result, i.e. disadvantage for the inner turbine and advantage for the outer turbine.
Finally, this work accomplishes the twin-rotor mechanism.
The results show that the inner turbine integrated with three blades outer turbine and turning contrarily received the best working efficiency of 21.6% at wind speed 8 m/s.
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