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

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) 2

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 3

Towing resistance: H-851 Modification 4

Current Applications – H-851 Modification  Float-over Topsides installation in Woodside Australia  Modification of H-851 5

Current Applications – H-851 Modification  Mid-bow shape - Final shape concepts - CFD computations to determine which shape has lower resistance 10% 3%  Results - More than 10% tow-resistance reduction - Another 3% tow-resistance reduction by applying wing-tanks 6

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 7

CFD Analysis– Morphing Mesh  Morphing mesh used to include effect of bottom 8

Results - Morphing mesh, h/d = 0.40 Ca-cfd = 1.57 [-], Ca-mt = 1.49 [-] 2 2 1.8 1.8 Ca-mt 1.6 1.6 Ca [-] Ca [-] Mean-mt Ca-mt Ca-cfd Mean-mt 1.4 1.4 Mean-cfd 1.2 1.2 1 1 0 0 0.1 0.1 0.2 0.2 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.6 0.7 0.7 0.8 0.8 0.9 0.9 1 1 B1-cfd = 0.043 [-], B2-cfd = 4.63 [-], B1-mt = 0.072 [-], B2-mt = 3.03 [-] 0.2 0.2 0.15 0.15 Be-mt Be [-] Be [-] Be-mt Trend-mt 0.1 0.1 Trend-mt Be-cfd Trend-cfd 0.05 0.05 0 0 0 0 0.1 0.1 0.2 0.2 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.6 0.7 0.7 0.8 0.8 0.9 0.9 1 1 KC [-] KC [-] 9/2 0

Added mass of ballast module 10

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 11

Open water thruster – Force definitions T unit : 6 component frame T prop & Q prop : on shaft T nozzle : on support 12

Open water thruster - Moving Reference Frame Disadvantage MRF: # Cells Option: Momentum source 13

Loss of accurate thrust component using AMS T nozzle AMS = 60% of T nozzle MRF During model tests all force components are measured MRF is used 14

Thruster wake development below SSCV 15

Pressure distribution – 8 thrusters active 16

Thrust efficiency, 4kn current        2 2 F F F F , , , ,  X TH X CUR Y TH Y CUR C  TH T OW 17

Validation on full scale: Thialf 18

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  All thrusters azimuth 0 ° Top view  P1 & S1  P2 & S2  P3 & S3  P1, P2, S1 & S2  P1, P3, S1 & S3  P2, P3, S2 & S3 20

Bar plots ratio’s Thialf test data vs. CFD: Effect Thrust Settings Relative speed (wrt Case 4) Test data CFD results 1.00 1.00 0.85 0.77 0.71 0.71 0.68 0.66 0.63 Same 0.62 trends! 0.53 0.47 0.45 0.43 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 21

Summary  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! 22