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flow in porous media + heat and mass transfert

Posted 15 févr. 2011, 05:11 UTC−5 Fluid & Heat, Heat Transfer & Phase Change 3 Replies

Joaquin
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Hi,

I have a 2D model where I want to model flow in porous media (Darcy's law), mass transfert (solute transport + diffusion) and heat transfert (convection and conduction). However, when I try to solve them both together, because they are coupled, I get this following message:

Error:
Failed to find consistent initial values.
Undefined_value_found_Solvermodel
Undefined value found in the stiffness matrix.
There are 25 equations giving NaN/Inf in the matrix rows for the variable MB
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
There are 25 equations giving NaN/Inf in the matrix rows for the variable T
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
There are 25 equations giving NaN/Inf in the matrix rows for the variable X
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
There are 25 equations giving NaN/Inf in the matrix rows for the variable rho_H2O
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
There are 25 equations giving NaN/Inf in the matrix rows for the variable rho_MS
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
There are 25 equations giving NaN/Inf in the matrix rows for the variable wCO2
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
There are 25 equations giving NaN/Inf in the matrix rows for the variable wO2
at coordinates: (0.630536,0.00738895), (0.635249,0.00961293), (0.632893,0.00850094), (0.638481,0.00887769), (0.636865,0.00924531), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns

Last time step is not converged.


What could the problem be ?
3 Replies Last Post 13 janv. 2012, 03:20 UTC−5
COMSOL Moderator

Hello Joaquin

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Jamal Alshaikhali
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Posted: 1 decade ago 12 janv. 2012, 21:36 UTC−5
I have the same problem. you have to check your intial and boundary conditions
Jamal
I have the same problem. you have to check your intial and boundary conditions Jamal
Mohamadreza Nassajian Moghadam
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Posted: 1 decade ago 13 janv. 2012, 03:13 UTC−5
I had exactly the same error when I modeled a poroelastic model. and I found that the problem was in material properties. I had a wrong magnitude for poisson ratio and when I changed it is was Ok. check material properties or boundary conditions.
I had exactly the same error when I modeled a poroelastic model. and I found that the problem was in material properties. I had a wrong magnitude for poisson ratio and when I changed it is was Ok. check material properties or boundary conditions.
Mohamadreza Nassajian Moghadam
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Posted: 1 decade ago 13 janv. 2012, 03:20 UTC−5
PS: how you did the coupling? because I want to model heat transfer in a porous media. but for that you should input the velocity of solute inside porous matrix.but for my model this velocity should be get form another poroelastic model which determine the velocity field inside matix when I apply cyclic presure on my system in each time step. that's why first I modeled a poroelastic model to calculate velocity field but I don't know how should I extract this velocity field in each time step and put it as a input for heat transfer model. in fact I don't know how to couple them!
PS: how you did the coupling? because I want to model heat transfer in a porous media. but for that you should input the velocity of solute inside porous matrix.but for my model this velocity should be get form another poroelastic model which determine the velocity field inside matix when I apply cyclic presure on my system in each time step. that's why first I modeled a poroelastic model to calculate velocity field but I don't know how should I extract this velocity field in each time step and put it as a input for heat transfer model. in fact I don't know how to couple them!

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