Numerical roughness modeling and its effects on power production estimations of wind turbines in icing conditions

Date

2025-1

Author

Sarıbel, Eda Bahar

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Ice accretion is a serious problem for wind turbines in cold climates. Since cold climates have higher wind energy capacity, the majority of wind turbines have been installed in these regions. Ice masses accumulating on wind turbines alter the surface geometry, leading to an greater drag force and reduced lift force. Accumulated ice can damage blades and reduce the power generated by wind turbines. Modeling the surface roughness of accreted ice is crucial for the accuracy of icing simulation. It alters the boundary layer characteristics and the heat transfer parameters on the ice surface. This research investigates the power production of iced wind turbines using surface roughness modeling. The Extended Messinger model, incorporating an improved ice roughness model, is used to simulate ice accumulation. The improved ice roughness model represents ice roughness based on ambient conditions and ice mass behavior. The calculated ice roughness is used in boundary layer development calculations, including the transition of laminar boundary layer to turbulent boundary layer. Power generation on clean and iced blades is calculated using the Blade Element Momentum (BEM) method. The Hess-Smith Panel Method is used to calculate the lift and drag coefficients of clean and iced blade sections. The surface velocity calculated using the Hess-Smith Panel Method is used as the edge velocity in the integral boundary layer method. The integral boundary layer method is employed to determine the convective heat transfer coefficient, skin friction coefficient, and displacement thickness. The effects of viscosity in the boundary layer are accounted for by adjusting the effective body through the displacement thickness in the calculations. The Lagrangian approach, which requires the flow field velocity components obtained from the panel method for the droplet equation of motion, is adopted for droplet trajectory analysis. Icing formations under different conditions and on various geometries are modeled. As a result of these formations, power losses due to icing are calculated. It is determined that the primary factors affecting power loss are wind speed and flow direction. The roughness model used does not have a significant impact on power losses.

Subject Keywords

Wind turbine, Atmospheric icing, Roughness, Extended messinger model

URI

https://hdl.handle.net/11511/113478

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Graduate School of Natural and Applied Sciences, Thesis