1 / 20

Aero-Hydro-Servo-Elastic Analysis of Floating Wind Turbines with Tension Leg Moorings

Aero-Hydro-Servo-Elastic Analysis of Floating Wind Turbines with Tension Leg Moorings. Erin Bachynski, PhD candidate at CeSOS erin.bachynski@ntnu.no May 15, 2013.

giulio
Download Presentation

Aero-Hydro-Servo-Elastic Analysis of Floating Wind Turbines with Tension Leg Moorings

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Aero-Hydro-Servo-ElasticAnalysisofFloating Wind TurbineswithTension Leg Moorings Erin Bachynski, PhDcandidate at CeSOS erin.bachynski@ntnu.no May 15, 2013 www.cesos.ntnu.no CeSOS – Centre for Ships and Ocean Structures

  2. Floatingwindturbineconcepts studied at CeSOS We need to understand floating wind turbine behavior so that we can bring the cost down Spar Semi-submersible TLP

  3. Tension Leg Platform (TLP) • Stability from tension legs, implying motions as an inverted pendulum • Small motions (+) • Flexible w.r.t. water depth (+) • Smaller steel weight (+) • Small footprint area on seabed (+) • Challenging installation (-)

  4. TLPWT Design Moon, 2010 • Displacement • Increasescost • Decreases risk ofslack • Pontoon radius • Increasesstability • Increases hull loads • Tendons Shimada, 2011 MIT-NREL TLPWT (Matha, 2009) Botta, 2009

  5. Integratedaero-hydro-servo-elasticanalysis control aerodynamics structural dynamics Challenges: -complexity -tightcoupling -nonlinear -time domain -long term periods -transient (faults) hydrodynamics Source: NREL/Wind powertoday, 2010.

  6. Aerodynamics J. de Vaal, 2012

  7. Control system • Serves to • regulate rotor rotation speed • regulate power output • protect structure • Actions • Change generator torque • Change blade pitch

  8. Blade pitch mechanism failures Contribution to failure rate (failures/turbine/yr) (%) Jiang, 2012 PhD candidates at CeSOS studying the effects of control system failures on different platforms : Z. Jiang, M. Etemaddar, E. Bachynski, M. Kvittem, C. Luan, A. R. Nejad Pitch system Wilkinson et al., 2011

  9. What happens if one blade stops pitching? TLP, U=20m/s, Hs = 4.8m, Tp = 10.8s Continue operating with faulted blade Fault occurs Shut down turbine quickly

  10. Comparison of controller fault effects on different platforms Semi-Sub 1 Semi-Sub 2 Spar TLP

  11. Environmental/Fault Conditions Max. thrust 50 yr. storm Ext. turb. * Simulation length after 200s initial constant wind period

  12. No fault Blade seize Blade seize + shutdown Grid loss + shutdown Storm condition Extreme turbulence at rated speed Tower Top FA Bending Moment

  13. Hydrodynamics aerodynamics control • Large volume structures: potential flow • First order • Second order sum-frequency • Slender structures: Morison’s equation • Tension-moored structures: ringing forces (3rd order) hydrodynamics

  14. Structural Modeling aerodynamics control structural dynamics hydrodynamics Flexible beam elements (tower, blades, mooring system) Rigid hull Global model – simplified generator

  15. Pitch TLPWT Parametric Design Study: • Diameter • Water Depth • Pontoon Radius • Ballast Fraction • 45 resulting designs • 7 environmental conditions Tower Base Bending Line Tension

  16. Concluding remarks • TLP wind turbines present complex, unanswered design and analysis challenges • Numerical simulations require coupled aero-hydro-servo-elastic tools and expertise • A wide variety of environmental and operational conditions must be considered • In our studies of floating wind turbines at CeSOS we hope to provide insights that can help inform designers and regulatory bodies

  17. Thankyou !

  18. TLPWT + 3 Point Absorbers • Preliminary results indicate no significant change in power output for WEC or WT by combining • Reduced tendon tension variation (5-10%) and motions % difference calculated as [(TLPWTWEC) – TLPWT]/TLPWT

  19. Simo-Riflex-AeroDyn Java: control AeroDyn: aerodynamic forces • Nonlinear time domain coupled code (Riflex: MARINTEK) • Single structural solver • Aerodynamic forces via DLL • Advanced hydrodynamics (Morison, 1st and 2nd order potential, ringing) (SIMO: MARINTEK) • Control code (java) for normal operation and fault conditions • Good agreement with HAWC2 (land-based and spar, including fault) SIMO: wave forces Riflex: structural deflections, time stepping

More Related