Optimization of wind turbine rotors - using advanced aerodynamic

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Optimization of wind turbine rotors - using advanced aerodynamic and aeroelastic
models and numerical optimization
Døssing, Mads
Publication date:
2011
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Citation (APA):
Døssing, M. (2011). Optimization of wind turbine rotors - using advanced aerodynamic and aeroelastic models
and numerical optimization. Roskilde: Risø National Laboratory for Sustainable Energy, Technical University of
Denmark. Risø-PhD, No. 69(EN)

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Optimization of wind turbine rotors - using
advanced aerodynamic and aeroelastic
models and numerical optimization

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Mads Døssing
Risø-PhD-69(EN)
Ma(cid:92) 2011
Author: Mads Døssing Risø-PhD-69(EN)
Title: Optimization of wind turbine rotors - using advanced ISBN 978-87-550-3861-5
Ma(cid:92) 2011
aerodynamic and aeroelastic models and numerical optimization
Division: Wind energy division

Pages: 181
Tables:
References:
Information Service Department
Risø National Laboratory for
Sustainable Energy
Technical University of Denmark
P.O.Box 49
DK-4000 Roskilde
Denmark
Telephone [phone]
[email protected]
Fax [phone]
www.risoe.dtu.dk
Summary
During the last decades the annual energy produced by wind turbines has in-
creased dramatically and wind turbines are now available in the 5MW range.
Turbines in this range are constantly being developed and it is also being in-
vestigated whether turbines as large as 10-20MW are feasible. The design of
very large machines introduces new problems in the practical design, and opti-
mization tools are necessary. These must combine the dynamic effects of both
aerodynamics and structure in an integrated optimization environment. This is
referred to as aeroelastic optimization.
TheRisøDTUoptimizationsoftwareHAWTOPThasbeenusedinthisproject.
The quasi-steady aerodynamic module have been improved with a corrected
bladeelementmomentummethod. Astructuremodulehasalsobeendeveloped
which lays out the blade structural properties. This is done in a simplified way
allowing fast conceptual design studies and with focus on the overall properties
relevant for the aeroelastic properties. Aeroelastic simulations in the time do-
main were carried out using the aeroelastic code HAWC2. With these modules
coupled to HAWTOPT, optimizations have been made. In parallel with the
developments of the mentioned numerical modules, focus has been on analysis
andafundamentalunderstandingofthekeyparametersinwindturbinedesign.
This has resulted in insight and an effective design methodology is presented.
Using the optimization environment a 5MW wind turbine rotor has been opti-
mizedforreducedfatigueloadsduetoflapwisebendingmoments. Amongother
thingsthishasindicatedthatairfoilsforwindturbinebladesshouldhaveahigh
lift coefficient. The design methodology proved to be stable and a help in the
otherwise challenging task of numerical aeroelastic optimization.
ii
Resum´e
I de sidste 10-20˚ar er der sket en dramatisk øgning i den˚arlige energimængde
produceret af vindmøller, og disse er nu tilgængelige i 5 MW klassen. Møller
i denne klasse bliver konstant udviklet, og det bliver ligeledes undersøgt om
møller s˚a store som 10-20 MW er realiserbare. Design af meget store maskiner
introducerer nye praktiske problemer, og optimerings-værktøjer er nødvendige.
Disseskalkombinerededynamiskeegenskaberafb˚adeaerodynamikogstruktur
i et integreret optimerings værktøj. Dette benævnes aeroelastisk optimering.
RisøDTU’soptimeringsprogramHAWTOPTerblevetbenyttetidetteprojekt.
Detkvasi-statiskeaerodynamik-modulerblevetforbedretmedenforbedretblad
element metode. Et struktur modul, der udlægger bladets strukturelle egensk-
aber, er ogs˚a blevet udviklet. Dette gøres p˚a en forenklet m˚ade, der muliggør
hurtige design studier p˚a koncept basis, og med fokus p˚a de overordnede egen-
skaber der er vigtige for de aeroelastiske egenskaber. Aeroelastiske simuleringer
foretaget i tidsdomænet er udført ved brug af HAWC2. Med disse moduler
koblet til HAWTOPT er der lavet optimeringer. Parallelt med udviklingen
af de nævnte moduler er der ogs˚a fokuseret p˚a analytiske analyser og p˚a en
fundamental forst˚aelse for nøgleparametrene i design af vindmøller. Dette har
resulteret i indsigt, og en effektiv design metode bliver præsenteret.
Vedbrugafoptimerings-værktøjeteren5MWvindmøllevingeblevetoptimeret
med henblik p˚a en reducering af udmattelses-lasterne fra de flapvise bøjnings
momenter. Detteharblandtandetindikeret,atvingeprofilertilvindmøllerskal
have en høj lift koefficient. Design metoden var stabil og en stor hjælp i den
udfordrende opgave, som numerisk aeroelastisk optimering er.
iv
Preface
This Ph.D. thesis has been prepared at Risø DTU National Laboratory for
SustainableEnergy,WindEnergyDepartment(VEA)AeroelasticDesignGroup
(AED) - Technical University of Denmark (DTU), during the period from 2008
to2011asapartialfulfillmentoftherequirementsforacquiringthePh.D.degree
inengineering. TheworkhasbeensupervisedbySeniorScientistChristianBak
(Risø DTU) and co-supervised by Research Specialist Helge Aagaard Madsen
(Risø DTU) and Senior Scientist Mac Gaunaa (Risø DTU).
TheprojectwasfundedbyVEA,RisøDTU,andpartlyfundedbytheprojects:
• ”Development of Adaptive Trailing Edge Flap (ATEF) System for Wind
Turbines” funded by the Advanced Technology Foundation.
• ”Light Rotor” funded by Energy Technological Development and Demon-
stration Program, EUDP2010 I.
I would like to thank Marianna for her loving support during the PhD study.
vi
Papers included in the thesis
[D] Madsen HAa, Bak C, Døssing M, Mikkelsen R, Øye S. Validation and
modification of the Blade Element Momentum theory based on compar-
isons with actuator disc simulations.
Wind Energy, 2010. Published
[E] Døssing M, Madsen HAa, Bak C. Aerodynamic optimization of wind
turbine rotors using a BEM method with corrections for wake rotation
and expansion.
Wind Energy, 2010. Submitted
[F] Døssing M, Bak C. A numerical and analytical investigation of blade
fatigue loads on the NREL 5MW wind turbine.
Wind Energy, 2010. Submitted