Integrated Aeroelastic Optimization of Small Wind Turbine Blades Using Multi-Objective Evolutionary Algorithms and Fluid-Structure Interaction Analysis

Abstract

The design of small horizontal axis wind turbine blades requires simultaneous consideration of aerodynamic efficiency and structural integrity, yet most optimization studies address these objectives in isolation or employ simplified structural models that neglect dynamic aeroelastic effects. This investigation presents a comprehensive multi-objective optimization framework that integrates two-way fluid-structure interaction analysis with a non-dominated sorting genetic algorithm to optimize blade geometry for a 5 kW horizontal axis wind turbine. The design variables encompass chord distribution, twist angle variation, and tip speed ratio, while constraints ensure structural safety through limitations on maximum stress, tip deflection, and natural frequency separation. The optimization objectives are to maximize the power coefficient and minimize blade mass. Computational fluid dynamics simulations employ the k-ω SST turbulence model with a sliding mesh interface to capture rotor rotation effects, while the structural analysis uses finite element methods with composite material properties. The Pareto-optimal solutions reveal a trade-off frontier where a 14.3% improvement in power coefficient can be achieved with a 9.8% mass reduction compared to the baseline design. Detailed flow field analysis demonstrates that optimized twist distribution delays flow separation at inboard sections, while modified chord distribution reduces tip vortex strength by 23%. The two-way coupling reveals that blade flexibility introduces a phase lag in aerodynamic force generation that reduces peak torque by approximately 2.8% but also attenuates fatigue-inducing load fluctuations. The optimized blade exhibits a 31% reduction in maximum principal stress and a 26% decrease in tip deflection, indicating substantially improved structural reliability. The framework provides a practical methodology for small wind turbine blade design that balances competing performance objectives while ensuring safe operation under realistic operating conditions.