CFD Analysis for the Improvement on Power Efficiency of Savonius Wind Rotors in Parallel Matrix System
|關鍵字:||沙伯紐式風車;並聯矩陣系統;功率係數;Savonius wind rotor;parallel matrix system;Cp (power coefficient)|
This study employs a computational fluid dynamics (CFD) software, Fluent, to analyze the flow fields around two-bladed Savonius wind rotors and their corresponding performances. This research includes three cases: the first one is a study of a single Savonius wind rotor, the second is the parallel matrix system, consisting of four two-bladed Savonius wind rotors, and the last one is the parallel matrix system of ten two-bladed Savonius wind rotors. All of the cases are carried out by the corresponding parametric studies, whose parameters include the wind velocity and tip speed ratio. After that, the influence of wind direction change on the parallel system is also studied. Then, comparisons between the systems mentioned above are discussed. The simulation results show that the maximum Cp value of one single Savonius wind rotor is 0.191 at tip-speed ratio 0.8; the parallel matrix system with four Savonius wind rotors is 0.402 at tip-speed ratio 0.9; the parallel matrix system with ten Savonius wind rotors is 0.438 at tip-speed ratio 0.7. The average Cp of the parallel matrix system with ten Savonius wind rotors is 2.25 times higher than that in one single Savonius wind rotor and the average Cp of the parallel matrix system with four Savonius wind rotors is 2.07 times higher than that in one single Savonius wind rotor. However, the average Cp of the parallel matrix system with ten Savonius wind rotors is 1.08 times higher than that in the parallel matrix system with four Savonius wind rotors. The Cp of these three cases slightly increase with wind speeds at the same tip speed ratio. The higher performance of parallel matrix system is resulted from the positive interaction between these Savonius wind rotors, and the flow fluctuation plays the major role in contributing to this effect, but this effect is strongly influenced by the change of wind direction. When wind direction is 0°, the Cp of the parallel matrix system becomes almost the same or even lower than that of a single one.
|Appears in Collections:||Thesis|
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