[Mehdi3031]

Hello Forum;
I am trying to introduce a species transport equation in interfoam for the liquid phase (Alpha1 = 1) as bellow:

Info << "solve ylEqn.H"<<endl;
    surfaceScalarField rho1Phialpha1 = rho1*phi*fvc::interpolate(alpha1);
    fvScalarMatrix ylEqn
    (
        fvm::ddt(alpha1*rho1, yl)
      + fvm::div(rho1Phialpha1, yl, "div(rhoPhiAlpha,yl)")
      - fvm::laplacian(alpha1*rho1*Dl, yl)
    );

This equation has been cited 100s of times and thats how people cancell out the gas domain(Alpha1=0) when solving the species balanse for the liquid phase and just solves it where ever Alpha1 is 1 or between 0 and 1.

But the problem is that I get crazy yl values at the interface where 0<Alpha1<1 as you can see in the attached photo! and if I don't bound the yl between 0 and 1 by force, it will go to infinity.
any Idea how to solve this numerical problem? did anybody have done it before?

Thanks a lot in advance

[Mehdi3031]

why my posts have always minimum views among the list??????!!!!
is there a trick or something to increase the view and reply??

[Cyp]

Hi,

Please, have a look at this paper :

https://www.sciencedirect.com/science/article/pii/S0009250918303944


Cheers,
Cyprien

[Mehdi3031]

Dear Cyprien,
Thank you so much for your response, I have seen the article, but the point is that you could use the Henry coefficient in this work and make a CST equation because you had a dilute solution which in my case I don't and cant do that. I have to solve the species equation separately for both phases like for phase 1:

fvScalarMatrix ylEqn
    (
        fvm::ddt(alpha1*rho1, yl)
      + fvm::div(rho1Phialpha1, yl, "div(rhoPhiAlpha,yl)")
      - fvm::laplacian(alpha1*rho1*Dl, yl)
    );

and the same for Phase 2; and then couple them with a source term. What I can't solve is that as soon as Alpha comes around in the species transfer equations, All goes wrong due to numerical problems introduced at the interface:

Any suggestion on that?

[Cyp]

You can if you put H=0.

[Mehdi3031]

I may explained bad,
(Using the notion in your paper): Cj,2 = Hj*Cj,1
so if Hj=0, means Cj,2 = 0 which means in phase two I have no Cj!!
In another word phase 2 (gas phase) is pure species i and liquid phase is binary mixture of Species j and i with Cj,1!
My problem is Ammonia-water mixture which means in both phases I have both species and it is non-diluted (Cj,2 = 0.95-0.995) and (Cj,1=0.1-0.6) which is as far as I know, not the case to use Henry coefficient.

Isn't that right?