Transport of Diluted Species in Porous Media
The Transport of Diluted Species in Porous Media node will use some of the variables solved in the Richards’ Equation interface. Darcy’s velocity, saturated volume fraction, and so forth, are denoted by the dl prefix. Other variables and material parameters are taken from the imported files.
Unsaturated Porous Medium 1
1
In the Model Builder under Component 1, click Transport of Diluted Species in Porous Media (tds) .
2
In the Physics toolbar click Domains  and select Unsaturated Porous Medium.
3
In the Settings window for Unsaturated Porous Medium, under Domain Selection select All domains from the Selection list.
4
Select Liquid under the Unsaturated Porous Medium node.
5
In the Settings window for Liquid, under Saturation change from Saturation to Liquid volume fraction, then enter dl.theta_l in the θl text field. This is the name for the liquid volume fraction calculated with the Richards’ Equation interface.
6
From the Liquid fraction time change list, choose Time change in pressure head. In the dHp/dt list, select Time change in pressure head (dl).
This is the variable from the Richards’ Equation interface.
7
Under Specify moisture capacity, enter dl.Cm in the Cm text field.
8
Couple the mass transport to the fluid flow. Locate the Convection section, select Total Darcy velocity field (dl) from the u list.
9
The diffusion coefficients are identical for all species. Enter Dl in the text fields for DL,c_a, DL,c_asx, and DL,c_asn.
10
Select the Gas 1 subnode under Unsaturated Porous Medium 1.
11
The gas diffusion coefficients are identical for all species. Enter Dg in the text fields for DGc_a, DG,c_asx, and DG,c_asn.
12
Find the Volatilization section and enter kg_a in the text field for kG,c_a and kg_asn in the text field for kG,c_asn.
The Porous Matrix 1 subnode keeps the default settings.
Adsorption 1
1
Under Transport of Diluted Species in Porous Media (tds), right-click Unsaturated Porous Medium 1 and choose Adsorption.
2
In the Settings window for Adsorption, locate the Adsorption section and select User defined from the Adsorption isotherm list.
3
Select the checkbox for c_a. In the cP,ca text field, enter kp_a*c_a.
4
Select the checkbox for c_asx. In the cP,casx text field, enter kp_as*c_asx.
5
Select the checkbox for c_asn. In the cP,casn text field, enter kp_asn*c_asn.
Dispersion
1
Right-click Unsaturated Porous Medium 1 and choose Dispersion.
2
For the Dispersion tensor list, select Dispersivity. For the Dispersivity model list, select Transverse isotropic. Enter alphar and alphaz.
Reactions 1
1
In the Physics toolbar click Domains  and select Reactions.
2
In the Settings window for Reactions locate the Domain Selection section. From the Selection list, choose All domains.
3
Locate the Reaction Rates section:
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In the Rc_a text field, enter dl.theta_l*(-r_1-r_3).
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In the Rc_asx text field, enter dl.theta_l*(r_1-r_2-r_4).
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In the Rc_asn text field, enter dl.theta_l*(r_2-r_5).
Outflow 1
1
In the Physics toolbar click Boundaries  and select Outflow.
2
In the Settings window for Outflow locate the Boundary Selection section and select boundaries 2, 8, 12, and 13 only. This corresponds to the bottom and right boundaries.
Concentration 1
1
In the Physics toolbar click Boundaries  and select Concentration.
2
In the Settings window for Concentration locate the Boundary Selection section. Select Boundary 5 only.
3
In the Concentration section select all three checkboxes.
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In the c0,c_a text field, enter c0.
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In the c0,c_asx text field, keep the default 0.
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In the c0,c_asn text field, keep the default 0.
Volatilization 1
1
In the Physics toolbar click Boundaries  and select Volatilization.
2
In the Settings window locate the Boundary Selection section. Select boundaries 6 and 11 only.
3
In the Volatilization section, enter Dg/d_s in the hc text field.
4
Select the Species c_a checkbox.
-
In the cGatm,ca text field, keep the default value 0.
5
Select the Species c_asn checkbox.
-
In the cGatm,casn text field, keep the default value 0.