the application of cfd at heerema marine...
TRANSCRIPT
The application of CFD at Heerema Marine Contractors STAR Global Conference 2012 - Noordwijk
Presented by: Harald Ottens Date: 21 March 2012
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Heerema Marine Contractors (www.heerema.com)
Marine Contractor in the offshore Oil and Gas Industry
HMC transports, installs and removes all types of offshore facilities
Focusing on complex projects, from conceptual design to completion
Operating 3 of the 4 largest construction vessels in the world
New vessel: DCV Aegir (2013)
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CFD applications within HMC
Current Affairs JIP - Current loads - VIM
Suction pile lowering - Added mass - Damping coefficients
H-851 - Tow resistance /
Shape optimization - Viscous damping
Current Loads - SSCV - Aegir
Thrust efficiency
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Towing resistance: H-851 Modification
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Current Applications – H-851 Modification
Float-over Topsides installation in Woodside Australia Modification of H-851
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Current Applications – H-851 Modification
10%
3%
Mid-bow shape - Final shape concepts - CFD computations to determine which shape has lower resistance
Results - More than 10% tow-resistance reduction - Another 3% tow-resistance reduction by applying wing-tanks
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Lowering Dynamics – Deep water installation
Resonance effects on dynamic behavior
- Load fluctuations in hoisting wires - Overload in cranes - Slack in wires
Maximum set-down velocity
3,000m
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CFD Analysis– Morphing Mesh
Morphing mesh used to include effect of bottom
9/20
Results - Morphing mesh, h/d = 0.40
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11
1.2
1.4
1.6
1.8
2
Ca [-]
Ca-mt
Mean-mt
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.05
0.1
0.15
0.2
Be [-]
KC [-]
Be-mt
Trend-mt
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11
1.2
1.4
1.6
1.8
2
Ca-cfd = 1.57 [-], Ca-mt = 1.49 [-]
Ca [-]
Ca-mt
Mean-mt
Ca-cfd
Mean-cfd
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.05
0.1
0.15
0.2
B1-cfd = 0.043 [-], B2-cfd = 4.63 [-], B1-mt = 0.072 [-], B2-mt = 3.03 [-]
Be [-]
KC [-]
Be-mt
Trend-mt
Be-cfd
Trend-cfd
Added mass of ballast module
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Thrust efficiency – Validation at model scale
Validation of thruster efficiency using CFD with available model test data (@ MARIN, The Netherlands)
- Open water thruster - Thruster-hull interaction with 8 active thrusters
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Open water thruster – Force definitions
Tunit: 6 component frame Tprop & Qprop: on shaft Tnozzle: on support
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Open water thruster - Moving Reference Frame
Disadvantage MRF: # Cells
Option: Momentum source
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Loss of accurate thrust component using AMS
Tnozzle AMS = 60% of Tnozzle MRF During model tests all force components are measured MRF is used
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Thruster wake development below SSCV
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Pressure distribution – 8 thrusters active
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Thrust efficiency, 4kn current
OW
CURYTHYCURXTHX
THT
FFFFC
2,,
2,,
Validation on full scale: Thialf
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Thialf – data sheet
Largest Deepwater Construction Vessel Tandem lift capacity 14,200t (15,600 short tons)
Dimensions:
- Length overall 201.6m (661 ft) - Length of vessel 165.3m (542 ft) - Width 88.4m (290 ft) - Depth to workdeck 49.5m (162 ft) - Draught 11.8 – 31.6m
(43 – 104 ft)
Class III Dynamic Positioning System - 6 x 5,500 kW – 360 azimuth (Wärtsilä)
More info: www.heerema.com
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Test cases
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All thrusters azimuth 0° P1 & S1 P2 & S2 P3 & S3 P1, P2, S1 & S2 P1, P3, S1 & S3 P2, P3, S2 & S3
Top view
1.00
0.47 0.43
0.62
0.71
0.85
0.77
1.00
0.53
0.45
0.63 0.66
0.71 0.68
All thrusters P1 & S1 P2 & S2 P3 & S3 P12 & S12 P13 & S13 P23 & S23
Case 4 Case 5 Case 6 Case 7 Case 8 Case 9 Case 10
Thialf test data vs. CFD: Effect Thrust Settings Relative speed (wrt Case 4)
Test data CFD results
Bar plots ratio’s
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Same trends!
Summary
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HMC has used CFD (STAR-CCM+) successfully for different subjects - Towing resistance / current loads - Added mass & Damping coefficients - Thrust efficiency
Validation on model scale and on full scale!