A Numerical Analysis of Power Efficiency of Wind Rotor System in Parallel Matrix
|關鍵字:||Savonius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. It is divided into two topics: one is a study of a single Savonius wind rotor, and the other is of a parallel matrix system. Both are carried out by the related parametric studies. The parameters for the single wind rotor are wind velocity and tip speed ratio. The ones for the parallel matrix system are wind velocity, tip speed ratio, phase angle difference and wind direction change. Then, comparison between the two systems is discussed. Besides, comparisons with other studies are also given. The simulation results show that the cp (power coefficient) of a single wind rotor slightly increases with wind speeds at the same tip speed ratio, and the performance of the one in atmosphere is lower than that inside the wind tunnel due to the influence of walls. In the 2-D simulation results of parallel matrix system, phase angle difference 90° can obtain the best cp that is 2.05 times of that by a single wind rotor. 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 45°, the cp of the parallel matrix system becomes almost the same or even lower than that of a single one. The maximal cp in the parallel matrix system by 3-D simulation is about 1.45 times of that by a single Savonius wind rotor. The ratio of 2-D cp to 3-D one is 1.28 in the single Savonius wind rotor condition and 1.83 in the parallel matrix system.
|Appears in Collections:||Thesis|
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