Quantification of 3D Ice Structures Accreted on a Wind Turbine Airfoil Model

Accurate quantification of 3D shapes of the complex ice structures accreted on wind turbine blades is highly desirable to develop ice prediction models for more accurate prediction of the aerodynamic performance degradation and power reduction due to the ice accretion on wind turbine blades. In the present study, an experimental investigation was conducted to quantitatively characterize the 3D shapes of the ice structures accreted over a DU91-W2-250 wind turbine airfoil model in the Icing Research Tunnel available at Iowa State University (ISU-IRT). A glaze icing condition and a rime icing condition that wind turbines usually experience in winter were duplicated by using ISU-IRT. A high-resolution non-intrusive 3D scanning system was used to make detailed 3D-shape measurements to quantify the complicated ice structures accreted on the wind turbine airfoil model as a function of the ice accretion time. The measurements results show that the complex 3D shapes of the ice structures accreted over the surfaces of the airfoil model under both glaze icing and rime icing conditions were well captured. It is found that the glaze ice accretion has stronger 3D features, in comparison to the rime ice accretion case, due to its wet nature. The measured 3D shapes of the complex ice structures at different ice accretion moments were also provided to demonstrate the progressive shape changes of the ice structures during the dynamic ice accretion process.