Robust Design Simulation of a Horizontal Axis Wind Turbine

Date

2023-12-28

Author

Altuğ Yalçın, Ayşe Hazal

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This thesis employs Robust Design Simulation (RDS) as an optimization method for wind turbine blade design, aiming to identify blade geometries less sensitive to uncertainties in blade aerodynamics. Various optimization scenarios target the reduction of thrust, flapwise bending moment, edgewise bending moment, tilt moment, and yaw moment, as well as the maximization of torque. Additionally, an Overall Evaluation Criteria (OEC) is defined, incorporating torque, flapwise and edgewise bending moments, to investigate optimized blade geometry minimizing the OEC. The objective is to obtain blade shapes less sensitive to uncertainties, particularly in airfoil aerodynamic coefficients. Both unconstrained and constrained design optimization scenarios are explored to assess the impact of design constraints such as power output, blade mass, and flapwise tip deflection. In addition to robust designs, conventional designs are generated as baseline cases to evaluate the impact of uncertainty sources. These optimization scenarios are investigated for both mean and maximum value optimization of loads under both uniform and turbulent inflow conditions. The RDS procedure involves screening design parameters for their significance levels, fitting response surface models to data generated using FAST simulations, and conducting Monte Carlo simulations to represent uncertainties in aerodynamic coefficients. Results indicate that resulting blade geometry highly depends on the load selection for minimization or maximization. Conventional design generally reduces (or increases) mean loads more than robust design, which demonstrates a trade-off between minimizing (or maximizing) mean loads and reducing variations around the mean simultaneously. In unconstrained optimization cases for thrust, flapwise, edgewise bending moments, and OEC loads are significantly decreased through reduced chord values and for thrust, flapwise, and edgewise bending moments increased twist values compared to constrained optimizations for the same cases. However, the resultant reduction in stiffness leads to decreased power output and increased flapwise tip deflection. In unconstrained optimization, the change in torque value is small compared to the increase in blade mass. For tilt and yaw moments in unconstrained optimizations, changes in blade mass, power, and flapwise tip deflection depend on the optimization scenario and design method, with no general rule.

Subject Keywords

Wind turbine design, Robust optimization, Response surface, Design of experiments, Monte Carlo simulations, Screening, Blade optimization

URI

https://hdl.handle.net/11511/107842

Collections

Graduate School of Natural and Applied Sciences, Thesis