Aerostructural Shape Optimization of Wind Turbine Blades Considering Site-Specic Winds

The global installed capacity of wind energy has been increasing steadily over the past decade, and the price of electricity derived from it has been continuously declining. While viable siting locations with with high quality wind resources still exist, improved turbine technology and cost reductions can expand the number of locations that are economically viable. This paper investigates the multidisciplinary nature of wind turbine design as it applies to turbine blades. The goal is to reduce the end unit cost of electricity, amortized over the turbine lifetime, for a particular location. A multidisciplinary design feasible (MDF) approach is used for solving the optimization problem. The blade aerostructural analysis couples a quasi-3D aerodynamic analysis | performed using a blade element momentum theory (BEM) method | with a six degree of freedom beam nite element model of the internal spar. Sensitivities for both the aerodynamic and structural analysis are computed using the complex step method. Finally, multipoint optimization of a small 5.0kW xed pitch \urban" wind turbine is performed based on the local wind velocity histograms.

[1]  A. Toffolo,et al.  Optimal design of horizontal-axis wind turbines using blade-element theory and evolutionary computation , 2002 .

[2]  Helge Aagaard Madsen,et al.  Optimization method for wind turbine rotors , 1999 .

[3]  J. Alonso,et al.  A Coupled-Adjoint Sensitivity Analysis Method for High-Fidelity Aero-Structural Design , 2005 .

[4]  Joaquim R. R. A. Martins,et al.  The complex-step derivative approximation , 2003, TOMS.

[5]  E. Eugene Larrabee,et al.  MINIMUM INDUCED LOSS WINDMILLS AND PROPELLERS , 1984 .

[6]  John E. Dennis,et al.  Problem Formulation for Multidisciplinary Optimization , 1994, SIAM J. Optim..

[7]  Michael A. Saunders,et al.  SNOPT: An SQP Algorithm for Large-Scale Constrained Optimization , 2002, SIAM J. Optim..

[8]  Kamran Behdinan,et al.  Particle swarm approach for structural design optimization , 2007 .

[9]  Pearu Peterson,et al.  Fortran to Python Interface Generator with an Application to Aerospace Engineering , 2001 .

[10]  Peter Fuglsang,et al.  Site-Specific Design Optimization of 1.5–2.0 MW Wind Turbines , 2001 .

[11]  M. Drela.  XFOIL: An Analysis and Design System for Low Reynolds Number Airfoils , 1989 .

[12]  David Greiner,et al.  Wind blade chord and twist angle optimization using genetic algorithms , 2006 .

[13]  Tim Cockerill,et al.  Site-specific design optimization of wind turbines , 1998 .

[14]  James Tangler,et al.  Wind Turbine Post-Stall Airfoil Performance Characteristics Guidelines for Blade-Element Momentum Methods: Preprint , 2005 .

[15]  Curran Crawford.  Re‐examining the precepts of the blade element momentum theory for coning rotors , 2006 .

[16]  E. Eugene Larrabee,et al.  MINIMUM INDUCED LOSS WINDMILLS AND PROPELLERS , 1983 .

[17]  Jens Nørkær Sørensen,et al.  Modelling and analysis of the flow field around a coned rotor , 2001 .

[18]  Martin Otto Laver Hansen,et al.  Aerodynamics of Wind Turbines , 2001 .