Generally, wind turbines have been constructed with three blades. Early analysis showed that as the number of blades increases, the power of extraction of wind turbines approaches the Betz limit. The increase in power extraction lessens as the blade number increases (greater increase from one to two blades than from two to three blades). The analysis assumed an ideal blade (zero drag) and no interaction between the blades. This paper investigates those two effects using CFD. Analysis of a 2D airfoil (S809) was compared to a finite 3D model. The 3D losses were then determined from those results. A stationary wind turbine model utilizing the analyzed 3D blades was then solved. The model was analyzed with varying the number of blades; the losses of blade interactions and drag effects were included in the efficiency of extracting the available power. It was determined that when analyzing an airfoil or a finite wing the power coefficient of the wind turbine increases, agreeing with previous analysis. However, when a stationary turbine model was analyzed, the power coefficient actually decreases as the number of blades increases.

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