Optimized design of wind turbine airfoil aerodynamic performance and structural strength based on surrogate model

• Published in: Ocean engineering Vol. 289; p. 116279
• Main Authors: Zhang, Qiang, Miao, Weipao, Liu, Qingsong, Xu, Zifei, Li, Chun, Chang, Linsen, Yue, Minnan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2023
• Subjects: Aerodynamic performance; Optimization design; Structural strength; Surrogate model; Wind turbine airfoil; Wind turbine airfoil; Aerodynamic performance; Structural strength; Surrogate model; Optimization design
• ISSN: 0029-8018
• DOI: 10.1016/j.oceaneng.2023.116279

Though offshore wind turbines have great potential for applications in ocean energy harvesting, their subject to complex unsteady aerodynamic loads. To obtain wind turbine airfoils with both aerodynamic performance and structural strength, an airfoil optimization method was proposed by adding the torsion constant to the objective function under the premise of improving the lift-to-drag ratio. The optimization method characterizes the airfoil geometric profile by using Class/Shape function transformation (CST) parameterization. The airfoil aerodynamics and the structural properties were solved by the computational fluid dynamics (CFD) method and Matlab program, respectively. To reduce the number of CFD calculations, a Kriging surrogate model was established. The combination of an optimized Latin hypercube sampling method and expected improvement (EI) points infill criteria is to improve surrogate modeling efficiency. The NREL 5 MW wind turbine blade was used as the research object. The NACA64618 with 18% relative thickness, the DU91-W2-250 with 25% and the DU97-W-350 with 35% were optimized by assigning different weights to aerodynamic and structural objectives based on airfoil position in the blade. The results showed that the aerodynamic performance of the optimized airfoils was improved. Subsequently, the three optimized airfoils were replaced in the same positions of the blade for lay-up design. The blade structural properties were calculated by finite element method (FEM) and it found that the blade torsion angle was reduced, which indicated that adding structural objectives in the airfoil optimization could enhance the blade structural performance. •The torsional constant of airfoil section is added to the structural objective.•Different weights are assigned to aerodynamic and structural objectives.•Expected improvement criterion is used to improve the efficiency of model optimization.•Surrogate-based optimization method obtains airfoil with better overall performance.•The structural strength of the three airfoils is verified by the finite element method.