Design of optimized wind turbine airfoils and blades at high Reynolds number

Abstract

With the development of offshore wind energy, researchers are endeavoring to design large offshore wind turbines. However, most of them still employ existing airfoils to design the aerodynamic shape of wind turbine blades (e.g., FFA-XX or DU-XX). Few focus on airfoil design at high Reynolds number. In this paper, a new method is introduced to optimize wind turbine airfoils at high Reynolds number. Four new airfoils are designed using a combination of B-spline functions and RFOIL version 5.4 software. Compared with FFA-W3-XX airfoils, the new airfoils series, named WQ-23-XX exhibit higher aerodynamic performance both in the smooth and rough condition. Second, the IEA 15 MW wind turbine blade is used as a baseline to develop an optimized mathematical model with a multi-objective function of maximizing power coefficient and dynamic bending moment. The results indicate that, although the maximum power coefficient increases by only 0.75% compared to the IEA 15 MW wind turbine, the amplitude of flap-wise bending moment and blade tip displacement are reduced by 4.3% and 7.0%, respectively. This reduction is beneficial for decreasing fatigue life and improving the operational reliability. This study serves as a guideline for designing offshore wind turbine airfoils at high Reynolds number and optimizing the aerodynamic shape of large offshore wind turbine blade to reduce the fatigue life.