# Species transport in Darcy flow

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June 29, 2015, 04:15
Species transport in Darcy flow
#1
Member

Yan Wang
Join Date: May 2015
Location: Beijing
Posts: 41
Rep Power: 7
Hi everyone,

I am trying to solve a species transport problem in darcy flow. Both viscosity and density depend on the species concentrations.

The equations and my calculation procedure are attached.

My test case is a point leakage at the location (0,0,0). I will post the case and solver here.

Hope you can help me.

Regards,

Wayne
Attached Files
 theory.docx (34.0 KB, 14 views)

Last edited by wayne14; June 29, 2015 at 10:26.

June 29, 2015, 04:45
#2
Member

Yan Wang
Join Date: May 2015
Location: Beijing
Posts: 41
Rep Power: 7
This is the solver and the two test case.

In test case Exo72D2Q0, the source strength is set to 0.
In this case, the air should just pile up without any movement.
The boundary conditions for pressure p seems to be ok now as follows:
Code:
```dimensions      [1 -1 -2 0 0 0 0];

internalField   uniform 101.325e3;

boundaryField
{
frontandback
{
type empty;
}
walls
{
}

up
{
type            fixedValue;
value           uniform 101.325e3;

}

down
{
type groovyBC;

value uniform 101361.69921;
fractionExpression "0";
}
}

// ************************************************************************* //```
Attached Images
 p.jpg (25.5 KB, 13 views) Rho.jpg (23.6 KB, 7 views)
Attached Files
 Exo72D2Q0.tar.gz (3.6 KB, 6 views) darcy2C1PFoam.tar.gz (3.5 KB, 6 views)

Last edited by wayne14; June 29, 2015 at 10:34. Reason: update

June 29, 2015, 05:01
#3
Member

Yan Wang
Join Date: May 2015
Location: Beijing
Posts: 41
Rep Power: 7
In test case Exo72D2, the source strength for CH4 is
Q Q [1 0 -1 0 0 0 0] 1.48e-5;// kg/s

This time the p still converge very fast, but the concentration (kg/kg) of CH4, 'TS2', would not converge below e-3
The concentration (kg/kg) of CH4 is shown in TS2.jpg and TS2 bigger.jpg.
The biggest problem is that TS2 does not meet the mass balance! Will someone be interested in helping me?
Attached Images
 TS2.jpg (19.0 KB, 8 views) TS2 bigger.jpg (43.2 KB, 13 views)

Last edited by wayne14; June 29, 2015 at 10:55.

 June 29, 2015, 11:53 #4 Member   Yan Wang Join Date: May 2015 Location: Beijing Posts: 41 Rep Power: 7 It seems that the problem have been solved after I correct the boundary conditions. However, I still wish that you can comment on my solver so that I can develop a better one in the future.

 September 26, 2016, 03:06 #5 New Member   Patrick Kastner Join Date: Apr 2016 Posts: 10 Rep Power: 6 Hi Yan, could you tell me how you corrected the BCs? I am trying to solve a similar problem at the moment. Kind regards, Patrick

September 26, 2016, 05:12
#6
Member

Yan Wang
Join Date: May 2015
Location: Beijing
Posts: 41
Rep Power: 7
Quote:
 Originally Posted by kostnermo Hi Yan, could you tell me how you corrected the BCs? I am trying to solve a similar problem at the moment. Kind regards, Patrick
Hi Patrick,

I will email you.

Regards,
Yan

 Tags darcy flow, density-variable, species transport, viscosity