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it doesn't work depends on thickness of electrolyte

Posted May 19, 2011, 2:32 p.m. EDT Chemical Reaction Engineering, Geometry, Studies & Solvers Version 4.1 3 Replies

Dicke
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Hi,

I am trying to make the modelling to predict potential distribution under the thin electrolyte. My model consists of 2 electrodes covered with thin electrolyte.

When the thickness of electrolyte was 1mm, computation was successful and I obtained reasonable result. But, when the thickness is thin (0.02mm), it doesn't work. Boundary conditions are totally same. Only difference between them is thickness of electrolyte. I don't know what problem this model has.
I would appreciate if someone gives me some advice about it. I attached 2 files above 2 examples.
3 Replies Last Post Feb 12, 2015, 2:38 p.m. EST
Lechoslaw Krolikowski
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Posted: 1 decade ago May 21, 2011, 10:19 a.m. EDT
Hi,
In the case of 0.02mm thickness your layer has only one mesh element across the layer. This is not enough. To obtain convergence you should increase the number of these elements .
Hi, In the case of 0.02mm thickness your layer has only one mesh element across the layer. This is not enough. To obtain convergence you should increase the number of these elements .
Dicke
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Posted: 1 decade ago May 25, 2011, 5:11 p.m. EDT
Hi, Lechoslaw,

Thank you for your comment.
I tried to make fine mesh not to across the thin layer and calculate again. But it still has problem.

Error message said,
Feature:Time Dependent solver1 (Sol1/t1)
Error:Nonlinear solver did not converge.

I attached file which mesh was made finer in the domain (thin electrolyte).
I would appreciate if someone tell me what this problem is.

Thank you,
Hi, Lechoslaw, Thank you for your comment. I tried to make fine mesh not to across the thin layer and calculate again. But it still has problem. Error message said, Feature:Time Dependent solver1 (Sol1/t1) Error:Nonlinear solver did not converge. I attached file which mesh was made finer in the domain (thin electrolyte). I would appreciate if someone tell me what this problem is. Thank you,
DW
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Posted: 9 years ago Feb 12, 2015, 2:38 p.m. EST
Hi,
You should change these things to get the model to converge:
(1) used mapped mesh for electrolyte domain with several elements through the thickness (perpendicular to surface of electrodes) and good density of nodes also in the horizontal (x direction);
(2) under Time-Dependent Solver > Fully Coupled, change Nonlinear method from Constant (Newton) to Automatic (Newton).
-DW
Hi, You should change these things to get the model to converge: (1) used mapped mesh for electrolyte domain with several elements through the thickness (perpendicular to surface of electrodes) and good density of nodes also in the horizontal (x direction); (2) under Time-Dependent Solver > Fully Coupled, change Nonlinear method from Constant (Newton) to Automatic (Newton). -DW

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