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quir February 13, 2017 11:00
NS Equations for multiphase flow in porous media
 
Hi everyone,

I've been stuck on following problem for a while:

I am trying to model multiphase (gas-liquid) flow through a packed bed for which I am using twoPhaseEulerFoam in OpenFOAM 3.0.1. To my understanding, all I need to do is change following equation
(1) \alpha_1 + \alpha_2 = 1
to
(2) \alpha_1 + \alpha_2 = \epsilon
where \epsilon is the porosity.
The alpha-equation solved in fluid.solve() is the one suggested by Weller in Rusche's thesis:
(3) \frac{\partial \alpha_1}{\partial t} + \nabla \cdot (\alpha_1(\alpha_1 \bar{U}_1 + \alpha_2 \bar{U}_2) + (\bar{U}_1 - \bar{U}_2) \alpha_1(1-\alpha_1))=0
However, this is only valid with equation (1). So, using equation (2) instead, an additional term appears:
(3) \frac{\partial \alpha_1}{\partial t} + \nabla\cdot (\alpha_1(\alpha_1\bar{U}_1 + \alpha_2\bar{U}_2) + (\bar{U}_1 - \bar{U}_2)\alpha_1(1-\alpha_1) + \alpha_1 \alpha_s U_2)=0
where \alpha_s=1-\epsilon. I have also added a momentum sink term to the momentum equations to account for liquid-solid and gas-solids interaction. My problem is that the \alphas are not bounded between 0 and \epsilon, but still go as high as 1.
I have tried defining an alphaMax in phaseProperties which should give a bound for the MULES solver, however, this doesn't make a difference.

Any ideas on what could be the problem?

Thanks

bibin.sme June 15, 2017 08:49
Did u get any solution to this problem... can you share your solver... ???

roshanak.rabiee878 May 25, 2020 10:48
Hi
have you solved your problem?
I have questions about how you add effect of relative permeability into your solver


Roshanak

Quote:
Originally Posted by quir (Post 636958)
Hi everyone,

I've been stuck on following problem for a while:

I am trying to model multiphase (gas-liquid) flow through a packed bed for which I am using twoPhaseEulerFoam in OpenFOAM 3.0.1. To my understanding, all I need to do is change following equation
(1) \alpha_1 + \alpha_2 = 1
to
(2) \alpha_1 + \alpha_2 = \epsilon
where \epsilon is the porosity.
The alpha-equation solved in fluid.solve() is the one suggested by Weller in Rusche's thesis:
(3) \frac{\partial \alpha_1}{\partial t} + \nabla \cdot (\alpha_1(\alpha_1 \bar{U}_1 + \alpha_2 \bar{U}_2) + (\bar{U}_1 - \bar{U}_2) \alpha_1(1-\alpha_1))=0
However, this is only valid with equation (1). So, using equation (2) instead, an additional term appears:
(3) \frac{\partial \alpha_1}{\partial t} + \nabla\cdot (\alpha_1(\alpha_1\bar{U}_1 + \alpha_2\bar{U}_2) + (\bar{U}_1 - \bar{U}_2)\alpha_1(1-\alpha_1) + \alpha_1 \alpha_s U_2)=0
where \alpha_s=1-\epsilon. I have also added a momentum sink term to the momentum equations to account for liquid-solid and gas-solids interaction. My problem is that the \alphas are not bounded between 0 and \epsilon, but still go as high as 1.
I have tried defining an alphaMax in phaseProperties which should give a bound for the MULES solver, however, this doesn't make a difference.

Any ideas on what could be the problem?

Thanks

regard December 26, 2020 11:25
hi all

can any body help me please, i want to change my alpha equation for two phase flow in porous media and i need to add effect of relative permeability and capillry pressure
thanks in advance


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