Kilian,
1. Thank you. I should have said "fraction" not "concentration". It is
all clear now.
2. You probably meant ReplaceCompEqIdx, not ReplaceComponentIndex, and
">= numComps" instead of "> numComps". It is clear now too, thanks!
Best regards,
Dmitry
On 11.02.2021 16:56, Kilian Weishaupt wrote:
Hi Dmitry,
I will try to answer your questions below:
1.) In Dumux, we consider mass or mole fractions (depending on whether
you set the Property "UseMoles" to true or false.
These fractions are always with respect to a given phase.
For example x^N2_gas would be the the mole fraction of the
component "N2" within the "gas" phase.
In what context did you encounter "concentration" in Dumux?
2.) This depends on what you set for the Property
"ReplaceComponentIndex". If you set that to a value > numComps,
you consider one balance equation for each component separately.
If, for instance, you have a H20-N2 Fluidsystem (2 components)
und you set ReplaceComponentIndex = 0,
the balance equation of the 0th component (H20) will be replaced
by a total mass/mole balance for the entire phase.
Depending on that is the Neumann flux. For ReplaceComponentIndex
= 0, you will inject a certain total mass/mole flow
for eqIdx = 0, while for ReplaceComponentIndex = 2 ( >
numComps), you will inject a certain mass mole/flow for only the H20
component.
Hope that helps!
Best wishes
Kilian
On 11.02.21 12:14, Dmitry Pavlov wrote:
Hello,
I ran into some strange issue in my porous flow simulation and I
think it may come from my misunderstanding of DuMux subtleties of
multi-component flow.
Could anybody please clarify things a bit for me?
1. What is a concentration -- is it the mass ratio of a component (e.
g. polymer) in the whole wetting phase (solution), or mass ratio of
the said component to the 0-th component (water)?
2. When I put neumann() conditions for injection or extraction
fluxes, should I assume that the flux that corresponds to the main
component is the molar flux of water, or the molar flux of phase
(water + polymer + other components if any)? I see examples in
dumux/test/porousmediumflow that seem to imply different answers to
this question.
Best regards,
Dmitry
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