Room:
Egbert-von-Hoyer Hall
Topic:
E. Design and systems engineering
Form of presentation:
Oral
Duration:
120 Minutes
Chaired by: K. Dykes, T. Chaviaropoulos
09:00
Design of an Aeroelastically Tailored 10 MW Wind Turbine Rotor
Dr. Frederik Zahle | Technical University of Denmark | Denmark
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Authors:
Dr. Frederik Zahle | Technical University of Denmark | Denmark
Carlo Tibaldi | Denmark
Christian Pavese | Denmark
Michael K. McWilliam | Denmark
José P. A. A. Blasques | Denmark
Morten Hartvig Hansen | Denmark
This work presents an integrated multidisciplinary wind turbine optimization framework utilizing state-of-the-art aeroelastic and strutural tools, capable of simultaneous design of the outer geometry and internal structure of the blade. The framework is utilized to design a 10 MW rotor constrained not to exceed the design loads of an existing reference wind turbine. The results show that through combined geometric tailoring of the internal structure and aerodynamic shape of the blade it is possible to achieve significant passive load alleviation that allows for a 9% longer blade with an increase in AEP of 8.7%, without increasing blade mass and without significant increases in ultimate and fatigue loads on the hub and tower.
09:20
Lightweight rotor design by optimal spar cap offset
Prof. Alessandro Croce | POLITECNICO DI MILANO | Italy
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Authors:
Prof. Alessandro Croce | POLITECNICO DI MILANO | Italy
Luca Sartori | Italy
Marco Stefano Lunghini | Italy
Luca Clozza | Italy
Carlo Luigi Bottasso | Italy
Pietro Bortolotti | Italy
Bend-twist coupling behavior is induced in a blade by displacing the suction side spar cap towards the leading edge, and the pressure side one in the opposite direction. Additional couplings are introduced by rotating the spar cap fibers. The structural configuration of the blade is optimized using an automated design environment. The resulting blade shows significant benefits in terms of mass and loads when compared to the baseline uncoupled one, so that this lightweight design can be leveraged to increase the rotor size, so that a larger energy yielding is achieved for the same hub loads.
09:40
Reduced Design Load Basis for Ultimate Blade Loads Estimation in Multidisciplinary Design Optimization Frameworks
Christian Pavese | DTU | Denmark
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Authors:
Christian Pavese | DTU | Denmark
Carlo Tibaldi | Denmark
Torben J. Larsen | Denmark
Taeseong Kim | Denmark
Kenneth Thomsen | Denmark
The aim is to provide a fast and reliable approach to estimate ultimate blade loads for a multidisciplinary design optimization (MDO) framework. For blade design purposes, the standards require a large amount of computationally expensive simulations, which cannot be eciently run each cost function evaluation of an MDO process. This work describes a method that allows integrating the calculation of the blade load envelopes inside an MDO loop. Ultimate blade load envelopes are calculated for a baseline design and a design obtained after an iteration of an MDO. These envelopes are computed for a full standard design load basis (DLB) and a deterministic reduced DLB. Ultimate loads extracted from the two DLBs with the two blade designs each are compared and analyzed. Although the reduced DLB supplies ultimate loads of dierent magnitude, the shape of the estimated envelopes are similar to the one computed using the full DLB.
10:00
A methodology to guide the selection of composite materials in a wind turbine rotor blade design process
Pietro Bortolotti | Technische Universität München | Germany
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Authors:
Pietro Bortolotti | Technische Universität München | Germany
Carlo L. Bottasso | Germany
Georg Adolphs | Germany
This work is concerned with the development of an optimization methodology for the composite materials used in wind turbine blades. Goal of the approach is to guide designers in the selection of the different materials of the blade, while providing indications to composite manufacturers on optimal trade-offs between mechanical properties and material costs. The method works by using a parametric material model, and including its free parameters amongst the design variables of a multi-disciplinary wind turbine optimization procedure. The proposed method is tested on the structural redesign of a conceptual 10 MW wind turbine blade, the spar caps and the shell skin laminates being subjected to optimization. The procedure identifies a blade optimum for a new spar caps laminate characterized by a higher longitudinal Young's modulus and higher cost than the initial one, which however in turn induce both cost and mass savings in the blade. In terms of shell skin, the adoption of a laminate with intermediate properties between a bi-axial one and a tri-axial one also leads to slight structural improvements.
10:20
On the Improvement of Convergence Performance for Integrated Design of Wind Turbine Blade Using a Vector Dominating Multi-objective Evolution Algorithm
Dr. Long Wang | Nanjing University of Aeronautics and Astronautics | China
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Authors:
Dr. Long Wang | Nanjing University of Aeronautics and Astronautics | China
Tongguang Wang | China
A novel multi-objective optimization algorithm incorporating evolution strategies and vector mechanisms, referred as VD-MOEA, is proposed and applied in the integrated design of wind turbine blade. In the algorithm, a set of uniformly distributed vectors is constructed to guide population in moving forward to the Pareto front rapidly and maintain population diversity with high efficiency. Two- and three-objective designs of 1.5MW wind turbine blade are carried out for the optimization objectives of maximum annual energy production, minimum blade mass, and minimum extreme root thrust. The results show that the Pareto optimal solutions can be obtained in one single simulation run and uniformly distributed in the objective space, maximally maintaining the population diversity. In comparison to conventional algorithms, VD-MOEA displays dramatic improvements in both convergence and diversity preservation for handling complex problems with multiple objectives, many variables and constraints.
10:40
Integration of prebend optimization in a holistic wind turbine design tool
Luca Sartori | Politecnico di Milano | Italy
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Authors:
Luca Sartori | Politecnico di Milano | Italy
Pietro Bortolotti | Italy
Alessandro Croce | Italy
Carlo Luigi Bottasso | Italy
This paper considers the problem of identifying the optimal combination of blade prebend, rotor cone angle and nacelle uptilt, within an integrated aero-structural design environment. Prebend is designed to reach maximum rotor area at rated conditions, while cone and uptilt are computed together with all other design variables to minimize the cost of energy. Constraints are added to the problem formulation in order to translate various design requirements. The proposed optimization approach is applied to a conceptual 10 MW offshore wind turbine, clearly highlighting the benefits of an optimal combination of blade curvature, cone and uptilt angles.