The application of CFD at Heerema Marine Contractors STAR Global - - PowerPoint PPT Presentation

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

• ffshore 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

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Results - Morphing mesh, h/d = 0.40

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1 1.2 1.4 1.6 1.8 2 Ca [-] Ca-mt Mean-mt 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.05 0.1 0.15 0.2 Be [-] KC [-] Be-mt Trend-mt 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1 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 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 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 CUR Y TH Y CUR X TH X TH

T F F F F C

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 19

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

22  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!