Download - Pauls Clavo Unos
-
7/27/2019 Pauls Clavo Unos
1/26
Deep Water Floater Concepts for
Offshore Wind Turbines.
Design, Modeling and Testing
Paul D. Sclavounos
Department of Ocean Engineering
Massachusetts Institute of Technology
-
7/27/2019 Pauls Clavo Unos
2/26
Benefits of Offshore Wind Energy
Wind speeds higher and less variable due to the absence of
obstacles (e.g. terrain, buildings, forests)
Environmental restrictions more lax at offshore sites
removed from densely populated areas (e.g. visual effects,
noise, interference with electromagnetic waves)
Large coastal and open seas areas available for exploration
at lower real estate costs relative to areas of comparable
size onshore
Proven Deep Water Floater technologies available from
Offshore Industry
-
7/27/2019 Pauls Clavo Unos
3/26
Challenges of Offshore Wind Energy
Large and variable water depths
Severe weather conditions
Development of reliable and flexible turbine,
electric generator and floater technologies
Cost of Development and Operation
-
7/27/2019 Pauls Clavo Unos
4/26
Floating Wind Turbines
Floating support structure increases the flexibility in locatingthe turbine in water depths of up to 200 meters
Turbines can be located closer to major population centersand into deeper waters instead of up a coast
Less of a problem for ocean front property owners andcoastal fishing / boating
Bottom features are not as large of a hindrance since
mooring lines or tethers are used instead of concrete bases
Individual Floaters Allow the Deployment of Large andVariable Number of Units
-
7/27/2019 Pauls Clavo Unos
5/26
Offshore Industry Floater Concepts
Gravity Tower
Semi-Submersible
Moored SPAR Buoy
Mini Tension Leg Platform
-
7/27/2019 Pauls Clavo Unos
6/26
-
7/27/2019 Pauls Clavo Unos
7/26
Semi Submersible Platform
-
7/27/2019 Pauls Clavo Unos
8/26
-
7/27/2019 Pauls Clavo Unos
9/26
Tension Leg Platform
-
7/27/2019 Pauls Clavo Unos
10/26
-
7/27/2019 Pauls Clavo Unos
11/26
Swim-Motion-Lines (SML)
Floater Response Simulation Model
Wave-Floater Interaction by Frequency Domain Methods(Swim)
Slow-Drift Response Simulation by Time Domain Method(Motion)
Frequency-to-Time-Domain Force Record Simulation byLinear and Quadratic FFT Methods (Motion)
Full Coupling with Nonlinear Mooring-Tether-Riser ModuleLines (Lines)
Fully Coupled Response Simulations in Random Waves
Response Statistics by Direct Analysis of Time-DomainRecords
-
7/27/2019 Pauls Clavo Unos
12/26
Spar and TLP SML Simulation Models
-
7/27/2019 Pauls Clavo Unos
13/26
Design I: Tethered Buoy
Water Depth 100-200m
-
7/27/2019 Pauls Clavo Unos
14/26
Design II: Spread Moored Buoy
Water Depth 100-200m
-
7/27/2019 Pauls Clavo Unos
15/26
Analysis Requirements
Wind Turbine Power/Thrust Determination
Linear and Nonlinear Hydrodynamic and Response
Analysis
Full Coupling of Wind Turbine and Floater Responses
Optimization of Floater Given Wind and Wave Loading
Extreme Responses Fatigue Analysis
-
7/27/2019 Pauls Clavo Unos
16/26
Simulation using ADAMSAerodynamic
Properties
of Wind Turbine
AERODYN
Module
Generator/Turbine
Control Module
Floater and Wave Parameters(Floater Input File)
ADAMS Solver
ADAMS
Control File
ADAMSModel File
FloaterLoading Module
ADAMS
Output Files
Floater SpecificOutput Files
-
7/27/2019 Pauls Clavo Unos
17/26
Floater Loading Module
Wave Characteristics
and Floater Dimensions
(Floater Input File)
Initial Calculation
Wave Spectrum
Added Masses
Wave Spectrum
and Elevation Output
ADAMS Marker
Number and Motions
Position, Velocities,and Accelerations
(from ADAMS)
Inertia Forces
Drag Forces
Forces
And Moments
for each frequency
band are summed
together.
Component
Loading Output
(returned to Adams)
Roll, Pitch, and
Yaw MomentsLoading Output File
-
7/27/2019 Pauls Clavo Unos
18/26
Above-Waterline Structure
Above waterline structure(tower and tower-top)
based on the WindPACT1.5-MW turbine*
Shaft height = 84.00 m
Tower height = 82.39 m Rotor diameter = 70.00 m
* All data for the 1.5-MW turbine are takenfrom input files for the FAST (Fatigue,
Aerodynamics, Structures, andTurbulence) code developed at theNational Renewable Energy Laboratory(NREL) National Wind TechnologyCenter (NWTC)
-
7/27/2019 Pauls Clavo Unos
19/26
General Description ofDesign 1
Cylindrical floating platformof draft T= 30 m and radius
r= 6 m Tension-leg mooring system
with 3 tendons
Radial distance of tendons
from the vertical axis of theplatform = 36 m
Water depth = 100 m
Unstretched length of lines =
69.940 m
Anchor Tension = 289.3 kips
-
7/27/2019 Pauls Clavo Unos
20/26
Design 1 (continued)
Natural frequencies
1
2
3
4
5
6
0.05 rad/s
0.05 rad/s
4.41 rad/s4.27 rad/s
4.27 rad/s
0.97 rad/s
=
=
=
=
=
=
-
7/27/2019 Pauls Clavo Unos
21/26
General Description ofDesign 2
SPAR floating platform of draftT= 30 m and radius r= 6 m
Taut-leg mooring system withfairlead locations at zF
= -30.0m and zF= 30.0 m (above thewaterline)
Radial distance of anchorsfrom the vertical axis of theplatform = 206 m
Water depth = 100 m
Unstretched length of top lines
= 240.10 m; unstretched lengthof bottom lines = 211.90 m
Anchor Tension = 550.8 kips
-
7/27/2019 Pauls Clavo Unos
22/26
Design 2(continued)
Natural frequencies
1
2
3
4
5
6
1.30 rad/s
1.30 rad/s
1.19 rad/s
1.77 rad/s
1.77 rad/s
0.68 rad/s
=
=
=
=
=
=
-
7/27/2019 Pauls Clavo Unos
23/26
Design I: Fully Coupled Response Simulations
Wind Speed 15 m/s, Sea State 6, Water Depth 100m
-
7/27/2019 Pauls Clavo Unos
24/26
Response Statistics in States 1 and 2
State 1: U= 22 knots, H1/3 = 3.0 m, and Tp = 8.69 s
State 2: U= 26 knots, H1/3 = 4.6 m, and Tp = 10.76 s
Response Standard Deviation
Env. State: 1 2 1 2
1 (m) 0.243 0.482 0.447 0.6022 (m) 0.246 0.484 0.446 0.565
3 (m) 0.020 0.053 0.067 0.134
4 (deg) 0.006 0.007 0.652 0.852
5 (deg) 0.007 0.008 0.556 0.647
6 (deg) 0.034 0.020 1.010 1.510
Design 1 Design 2
-
7/27/2019 Pauls Clavo Unos
25/26
Planned Work
Comparative Evaluation of Floater I & II Concepts in
Water Depths 100-200m
Determination of Optimum Floater Configuration in
given Weather Environment
Establish Analysis Steps for Floater-Turbine
System Certification
Perform Wind Farm Optimization Analysis
Perform Wind Farm Lifetime Economic Analysis
-
7/27/2019 Pauls Clavo Unos
26/26
Method Validation
Perform On Site Wind and Wave
Measurements
On Site Measurements on Floating Wind
Turbine Prototype
Prototype Instrumentation and Response
Measurement
Validation of Simulations with Measured and
Design Wind and Wave Conditions