Deep understanding on the impacts of leading edge erosion on the performance and flow characteristics of wind turbines is significant for the blade design and wind farms management. Pitting erosion and three levels of delamination are considered in the present study. The results show that the degrees of leading edge erosion have great influence on the flow separation, tangential force coefficient, normal force coefficient as well as the power output of the wind turbine. Leading edge erosion has the greatest impact on aerodynamics of the wind turbine at 15 m/s, where the maximum loss in the power output can reach up to 73.26%.

Severe erosion or delamination at the leading edge of blades has an adverse influence on the power loss of wind turbines. Obtaining relevant quantitative data and its mechanisms would help in the efficient management and maintenance of these turbines. In the present work, detailed analysis on the effects of various levels of leading edge delamination on the aerodynamics and flow characteristics of an S809 airfoil and, in turn, on the performance of the NREL phase VI rotor is conducted. The results indicated that an elongated leading edge separation bubble and two enclosed vortex systems appeared in the delaminated region of the airfoil when the delamination levels aggravate to a certain degree, while the trailing edge separation vortex can be observed for all delaminated airfoils. The aerodynamic performance of the wind turbine decreases with increasing delamination depth and increases with growing delamination depth. The most influential delamination length is 1% c, and the maximum power loss is 23.09% for the blade with the severe delamination case. A small area of deep leading edge delamination or defects may cause great power loss, which should not be ignored in practice engineering.

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