Numerical analysis of blade icing influence on the dynamic response of an integrated offshore wind turbine

When a wind turbine is working in a cold and humid environment, icing may occur which lead to its performance reduction or even blades fracture. In this paper, a CFD-WTIA (Wind Turbine Integrated Analysis) coupled method is established to analyze the blade icing process and its influence on the overall dynamic performance of an integrated jacket-support offshore wind turbine. Firstly, motions of the blades are calculated by the WTIA method and used as input into CFD. Then, dispersed multi-phase model and melting-solidification model are used to simulate the icing growth phenomenon of three-dimensional blades. The k-ε turbulence model is used to calculate the aerodynamic performance before and after icing. Finally, the aerodynamic results after blade icing are returned to WTIA for integrated dynamic response acquisition. At the same time, the dynamic response of the wind turbine under the combined influence of ice and sea ice is analyzed. Results show that the blade ice-accretion increases linearly along the blade span-wise direction and is mainly concentrated on the leading edge of the blade. Lift and drag coefficients are seen deceased and increased respectively after icing. Power production, generator torque, rotor speed, as well as blade vibration are quantitatively studied. The methodology and findings of this paper can provide a good reference for the safety performance evaluation of an icing offshore wind turbine.