air flow optimization for remediation using sparg diane fink liz hilkert
Post on 21-Dec-2015
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TRANSCRIPT
Air Flow Air Flow Optimization Optimization
for Remediation for Remediation using SPARGusing SPARG
Diane FinkDiane Fink
Liz HilkertLiz Hilkert
Significance and ObjectiveSignificance and Objective
Optimal airflow rates are important in Optimal airflow rates are important in remediation remediation – Ensure maximum contaminant volatilizationEnsure maximum contaminant volatilization– Prevent Prevent
channeling channeling Determine ideal Determine ideal
capillary pressurescapillary pressuresfor a one meter for a one meter soil column soil column – varying water varying water
table heightstable heights
SPARG InformationSPARG Information
Unix based program for one or two Unix based program for one or two dimensional column simulationsdimensional column simulations
Uses finite element-Galerkin's Uses finite element-Galerkin's formulation formulation
The airflow simulation model that is The airflow simulation model that is the basis for AirFixthe basis for AirFix– Includes contaminant transportIncludes contaminant transport
SPARG CalibrationSPARG Calibration
Only dependable data from Only dependable data from 2D model2D model
Capillary Capillary Head of Head of 10.15 m10.15 m
Calibration Calibration successfulsuccessful
Sensitivity Sensitivity AnalysisAnalysis
Sensitive Variables
Capillary Pressure Saturation
Atmospheric Pressure All
Soil Lambda Porosity Ave Saturation
Sensitivity
0.340 0.109 Min-Def 1.003
0.390 0.125 Def-Max 0.998
0.440 0.141
Atmospheric Pressure
Capillary Pressure at Y =0.4
Sensitivity
8.000 -0.524 Min-Def 29.032
10.000 0.276 Def-Max 6.509
12.000 1.076
SPARG InputsSPARG Inputs Constant Inputs:Constant Inputs:
– Psubd: 0.2 mPsubd: 0.2 m– Soil Lambda: 3.4Soil Lambda: 3.4– Porosity: 0.39Porosity: 0.39– Grid: 1,10 Grid: 1,10 – Grid Division: 0.1 mGrid Division: 0.1 m– Atmospheric Atmospheric
Pressure: 10 mPressure: 10 m
20 elements
22 nodes
Varied SPARG InputsVaried SPARG Inputs
Water Table Height:Water Table Height:– Half of Sand Height: 0.33 mHalf of Sand Height: 0.33 m– Full Sand Height: 0.67 mFull Sand Height: 0.67 m
Airflow Entry Rate (nodes 1 and 2):Airflow Entry Rate (nodes 1 and 2):– Varied by increasing air entry pressureVaried by increasing air entry pressure– Minimum for half full: 10.53 mMinimum for half full: 10.53 m– Minimum for full: 10.87 mMinimum for full: 10.87 m
Effect of Air Entry Pressure at Full Effect of Air Entry Pressure at Full Water Table Height (0.67 m)Water Table Height (0.67 m)
Saturation
Capillary Pressure
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Capillary Pressure (m)
Hei
gh
t (m
)
10.8910.9310.97
0
2
4
6
8
10
12
14
16
18
20
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Saturation (m)
Ele
me
nt
(-)
10.8910.9310.97
Effect of Air Entry Pressure at Half Effect of Air Entry Pressure at Half Water Table Height (0.33 m)Water Table Height (0.33 m)
Capillary Pressure
Saturation0
2
4
6
8
10
12
14
16
18
20
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Saturation (m)
Ele
me
nt
(-)
10.531
10.55
10.570
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Capillary Pressure (m)
Hei
gh
t (m
)
10.531
10.55
10.57
Graphical TrendsGraphical Trends Capillary pressure:Capillary pressure:
– linear relationship linear relationship with column heightwith column height
– indirectly indirectly proportional to proportional to water table height water table height
– directly directly proportional to air proportional to air entry pressure at entry pressure at lower water table lower water table heightsheights
pressures converge as air pressures converge as air reaches the top of the reaches the top of the column, which is column, which is atmosphericatmospheric
Saturation:Saturation:– nonlinear nonlinear
relationship with relationship with column heightcolumn height
– directly proportional directly proportional to water table height to water table height
– indirectly indirectly proportional to air proportional to air entry pressure at entry pressure at lower water table lower water table heightsheights
saturation levels converge saturation levels converge as air reaches the top of the as air reaches the top of the column, which is column, which is atmosphericatmospheric
ConclusionsConclusions
Full Water Table Height (0.67 m):Full Water Table Height (0.67 m):– Air entry pressure range: 10.871 – 10.89 m Air entry pressure range: 10.871 – 10.89 m
Half Water Table Height (0.33 m):Half Water Table Height (0.33 m):– Air entry pressure range: 10.531 – 10.55 mAir entry pressure range: 10.531 – 10.55 m