Impacts of Leading Edge Pitting and Delamination on Aerodynamic Characteristics of Wind Turbine Blades under Shear Inflow

Abstract

Undesirable performance degradation occurs when wind turbine operates in harsh environment, thus investigation of the impact of various degrees of leading edge erosion on the aerodynamic characteristics of wind turbine is significant and highly desirable. In this study, significant research efforts were made to explore the effects of leading edge pitting and delamination on blade surface streamlines, flow structures, pressure coefficients, and aerodynamic forces of horizontal wind turbine under shear inflow. The k-ω shear-stress transport turbulence model was adopted to close the three-dimensional incompressible Reynolds-averaged Navier-Stokes. The results indicate the existence of significant differences on surface streamlines between the smooth and eroded blade. The leading edge of the entire blade gets covered with the attached flow, while just a small area for the eroded blade is covered when it is at the lowest position. Moreover, small separation bubble appears at the suction surface of the section near the blade root, which grows bigger and induces a second vortex when the section moves to the middle of the blade and then the size gets smaller when the section is near the blade tip. With the increase of erosion, the pressure difference of blade surface decreases, indicating a severe decrease in performance of eroded blade. Furthermore, leading edge erosion causes a decrease in average torque coefficients by 19.75, 29.01, 41.82, and 42.54% for various leading edge erosion cases at the inflow wind speed of 10 ms-1, and 25.0, 49.6, 51.3, and 54.6% at the speed of 20 ms-1.

Keywords

• aerodynamic characteristics
• pitting and delamination
• shear inflow
• wind turbine blade