Wind Turbine Performance in Controlled Conditions: BEM Modeling and Comparison with Experimental Results

Abstract EN

Predictions of the performance of operating wind turbines are challenging for many reasons including the unsteadiness of the wind and uncertainties in blade aerodynamic behaviour.

In the current study an extended blade element momentum (BEM) program was developed to compute the rotor power of an existing 4.3 m diameter turbine and compare predictions with reported controlled experimental measurements.

Beginning with basic blade geometry and the iterative computation of aerodynamic properties, the method integrated the BEM analysis into the program workflow ensuring that the power production by a blade element agreed with its lift and drag data at the same Reynolds number.

The parametric study using the extended BEM algorithm revealed the close association of the power curve behaviour with the aerodynamic characteristics of the blade elements, the discretization of the aerodynamic span, and the dependence on Reynolds number when the blades were stalled.

Transition prediction also affected overall performance, albeit to a lesser degree.

Finally, to capture blade finite area effects, the tip loss model was adjusted depending on stall conditions.

The experimental power curve for the HAWT of the current study was closely matched by the extended BEM simulation.