Transcript Numerical Modeling of a Salinity Intrusion Barrier

Numerical Modeling of a Salinity Intrusion Barrier
Saltwater Intrusion Prevention System
Developed Through a
Cooperative Research & Development Agreement
Patented Technology owned by Saltwater Separation, LLC
•Saltwater Separation, LLC Team
•E. Robert Kendziorski
ERDC-CHL Team
Jose E. Sanchez, P.E.
Robert Bernard, PhD
[email protected]
Phu Luong, PhD
[email protected]
•[email protected]
•949.677.1991
•Charles H. Tate, P.E.
•[email protected]
•601.218.2173
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Salinity Intrusion Barrier System
OUTLINE
 Challenges
 Cooperative Research and Development Agreement
(CRADA)
 US Army Engineer Research and Development Center –
Coastal and Hydraulics Laboratory (ERDC-CHL)
 PAR3D
 Miraflores Locks
 Simulation basis
 Experiments
 Results
 Recommendations and Conclusions
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Salinity Intrusion Barrier System
CHALLENGES
 Miraflores Lake brackish condition
 Current estimates of 1ppt concentration (ERDC-CHL 2000
study)
 No salinity intrusion barrier or system in place
 Quality issues for some uses
 Increased traffic demand
 Current operations general range between 30 and 40 ships per
day
 Future expectations of up to 53 ships per day
 Unsteady flow in the downstream lock approach conditions
during emptying cycle
 Inconsistent navigation condition (1 out of 30 may impact the
lock structure, as per WPSI)
 Possible Canal expansion
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Salinity Intrusion Barrier System
CRADA
 What is it?
 Cooperative Research and Development Agreement
 Benefits
 Allows USACE to partner with other organizations
 Shares information, knowledge, discoveries
 Parties involved
 US Army Engineer Research and Development Center,
Coastal and Hydraulics Laboratory
 Water Processing Systems Incorporated
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Salinity Intrusion Barrier System
ERDC-CHL
 Expertise
 75 years experience in physical and numerical
hydraulic modeling
 250 personnel
 140 Engineers and Scientists
 56 with PhDs
 60 with MS degrees
 Resources
 Many numerical models available
 PAR3D chosen
 High Performance Computing Center on site
 Among the top 10 in the world
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Salinity Intrusion Barrier System
PAR3D
 What is it?
 3-dimensional incompressible flow numerical model
 Accommodates
 Deforming grids
 Free-surface displacement
 Multiple processors
 Capabilities include
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Heat and dissolved-gas transfer and transport
Salinity transport
Temperature stratification and mixing
Sediment and biomass transport (with oxygen demand)
Turbulence modeling including buoyancy
Flow driven by bubble plumes and mechanical mixers
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Salinity Intrusion Barrier System
PAR3D (CONTINUED)
 Governing equations
 Navier-Stokes equations for incompressible flow
 K-Epsilon turbulence model
 Pneumatic injection specialty
 Published in “Applied Mathematical Modeling”
 Independent peer review for application to independent
experimental data, 2000
 Previous applications
 Taylorsville Lake intake structure, internal flow in the
structure
 WES Riprap Test Facility, open-channel flow around a bend
 McCook Reservoir (in design), pneumatic bubble plume
application
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Salinity Intrusion Barrier System
MIRAFLORES LOCKS
INLAND SIDE
OCEAN SIDE
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Salinity Intrusion Barrier System
MIRAFLORES LOCKS
model grid area
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Salinity Intrusion Barrier System
INITIAL SIMULATION BASIS
 Average depth (50-ft)
 No tidal action
 No vessel
 Approximate bathymetry (el. –50ft)
 Lock exit structure modeled
 Channel width approximated (110 to 220-ft)
 Starting salinity
 10 ppt DS of miter gates (1000-ft stretch)
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Salinity Intrusion Barrier System
MODEL
Pacific Ocean
Guide wall
Miter gates
•Total length = 1000-ft
Wing wall
•110-ft wide
•50-ft deep
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Salinity Intrusion Barrier System
Model Simulations
 Existing conditions without salinity barriers
 During emptying cycle
 Simplified lock release (steady state outflow)
 15 min cycle with 3kcfs flow rate
 20 min after emptying cycle ends (re-stratification)
 Effects of bubble curtains
 With/without pneumatic injection
 Bubble curtain setup
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1 bubbler 400-ft from miter gates (WPSI feasibility report)
2 bubble curtains (100 & 200-ft from each other)
4 bubble curtains (100-ft from each other)
8 bubble curtains (50-ft from each other)
 Fresh water injection rates with 4 bubble curtains
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Salinity Intrusion Barrier System
EXISTING CONDITIONS:
3kcfs injection, after 15 min emptying cycle
Water injection
no injection, 20 min after cycle
(50-ft from miter gates)
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Salinity Intrusion Barrier System
BUBBLE CURTAINS vs. NO CURTAINS:
563 cfs fresh water injection – 3hr simulation
Water injection
(50-ft from miter gates)
water injection
water injection
bubbler
bubbler
bubbler
bubbler
bubbler
bubbler
bubbler
bubbler
563 cfs fresh water injection, 1100 scfm/curtain – 3hr simulation
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Salinity Intrusion Barrier System
FOUR BUBBLE CURTAINS:
water injection
bubbler
1100 scfm/curtain, 563cfs fresh water, 3hr animation (10min intervals)
bubbler
bubbler
bubbler
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Salinity Intrusion Barrier System
FOUR BUBBLE CURTAINS:
water injection
bubbler
1100 scfm/curtain, 563cfs fresh water, 9hr simulation
bubbler
bubbler
bubbler
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Salinity Intrusion Barrier System
Water injection rates (4 bubble curtain design)
Qw inj (cfs)
fresh water (0 ppt)
Time for < 1ppt
100-ft from gates
563
180 min
885
90 min
1198
60 min
1709
60 min*
1812
60 min*
(50-ft deep)
* Time reflects salinity concentration at 100-ft from miter gates
only. Lower concentrations were indicated further downstream
sooner.
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Salinity Intrusion Barrier System
ADDITIONAL SIMULATION BASIS
 Tidal fluctuations
 Max depth – 64ft
 Min depth – 44ft
 Vessel exiting lock chamber
 With propeller action
 Without propeller action
 Stratified salinity distribution
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Salinity Intrusion Barrier System
Tidal fluctuation comparison
Qw inj (cfs)
fresh water (0
ppt)
Time for < 1ppt
100-ft from gates
Time for < 1ppt
100-ft from gates
(44-ft deep)
(50-ft deep)
Time for < 1ppt
100-ft from
gates
563
120 min
180 min
270 min
1812
50 min
60 min
80 min
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(64-ft deep)
Salinity Intrusion Barrier System
Ship and propeller mixing characteristics
 Ship Model
 Dense grid
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2000-ft channel
Starting at US miter gates
Divided into 100-ft cells
Depth: 50 ft
 Panamax type ship
 965’l x 106’w x 39.5’d (centered in channel – exiting lock chamber)
 26-ft diameter propeller helix
 20,000 hp
 Simulation
 Initial conditions
 5 ppt starting 200-ft downstream of ship
 1 ppt inside of lock chamber
 563 cfs fresh water injection 100-ft from DS miter gates
 4 bubble curtain design
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Salinity Intrusion Barrier System
Ship and propeller mixing characteristics
Ship only
Stern
Ship
Bow
< 1 ppt
Ship with motor in operation
< 1 ppt
563 cfs fresh water injection, 1100 scfm/curtain – 1hr simulation
Initial condition: 5 ppt starting 200-ft downstream of ship
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Pacific Ocean
Salinity Intrusion Barrier System
Recommendations and Conclusions
 Conclusions
 Best design tested – 4 bubble plumes at 1100 standard
cfm/location with minimum 563 cfs fresh water inflow
 More air flow does not improve performance
 More air injection points does not improve performance
 Higher water flow rates do improve performance, up to a certain
limit
 Tidal fluctuations have minimal impacts on performance
 Ship and propeller have minimal impacts on performance
 Recommendations
 2D physical tests for salinity transfer at bubble plumes
 Experiments to study downstream conditions during emptying
cycle (turbulent currents – baseline conditions)
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