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Dispersion of ContaminantsDispersion of Contaminantsin the Oceanin the Ocean
Authors:• André Luiz Fadel - Mechanical Eng., M. Sc. / Petrobras• João Tornovsky - Chemical Eng. / Chemtech• Flávio Guimarães - Chemical Eng., M. Sc. / Chemtech
VIII International PHOENICSUsers Conference
Luxembourg, May 2000
chem
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Introduction I
VIII International Phoenics Users Conference
• Increasing environmental awareness
• Risk assessment
• Consequence Analysis
• “What-if” analysis
• CFD x correlations
• Realistic approach
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Introduction II
VIII International Phoenics Users Conference
• Off-shore oil platforms
• Aqueous solution discharge - submerged header
- salt water, light oil, heavy oil
- high temperature
• Impact estimation
• Mitigation approach, if needed
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Geometry and Grid
VIII International Phoenics Users Conference
• flat ocean bed
• submerged fraction of the platform disregarded
• header influence in the near field
• symmetry plane
• power-law grid far field
100 m
39 m
0.1 m/s@ 65oC, 100 psu
= 1.27 m
0.15 m/s 15oC
0.25 m/s 23oC
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Models
VIII International Phoenics Users Conference
• Density: influence of composition and temperature
• Difusion:
Set as a function of micro-mixing rate (EPKE)
PRNDTL(phi) = - GRND
),3(),3(),3( TCTCTC ooo
oo CTC 3),3(
oo TTTTC 32),3(
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Models
VIII International Phoenics Users Conference
• Sinking and Floating:
• Turbulence: stadard k- model
• Relaxation:
C1H
C1L
Z Z
CCV
t
C LHo
)11(11
5
2
10
vX
XTFAL
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Boundary Conditions
VIII International Phoenics Users Conference
• Stream Profile:
Inlet
- Velocity
- Temperature
- Salinity
• Stability condition: stratification / thermocline
Moderate stratification was used
Density
Outlet
- Pressure
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Results I
VIII International Phoenics Users Conference
• intermediate condition intermediate results
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Results II
VIII International Phoenics Users Conference
• Results agree with qualitative reports from literature
• No distinctive behaviour shown due to settling
C1 C3
C5
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Conclusions
VIII International Phoenics Users Conference
• Reasonable quantitative agreement with experimental data
• Good qualitative behaviour
• Understanding of plume sensibility to operational and environmental conditions
• Results indicate safe operation
