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2D Electrode Model Question
Posted Oct 30, 2012, 1:04 p.m. EDT 3 Replies
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Hello all,
I am attempting to model the time varying current distributions on 2 rectangular electrodes with with tabs. The model idea is that current flows into one electrode through its tab, then flows perpendicularly across a separator and into the other electrode and out its tab. The rest of the electrodes are electrically insulated except for the top tab boundary, where I define the current in (as a Terminal).
My sticking point is how to model this perpendicular (ionic) current in COMSOL. The equation governing this ionic current will be of the form J = (1/R)*(V_electrode1 - V_electrode2); essentially the ionic current is driven by the voltage difference between each electrode. I guess it boils down to the electrodes represented as a 2D network of resistors, each connected at a node by another resistor controlling the ionic current, forming a 3D matrix of resistors.
I am confused as how to specify this ionic current. Would it be represented as a current source on the face of each electrode? I assume i would also need two Electric Current modules, one for each electrode, so that I can solve for the voltage on each one.
I feel like this is a basic problem, but I must be missing something fundamental. I appreciate any input!
Ben
I am attempting to model the time varying current distributions on 2 rectangular electrodes with with tabs. The model idea is that current flows into one electrode through its tab, then flows perpendicularly across a separator and into the other electrode and out its tab. The rest of the electrodes are electrically insulated except for the top tab boundary, where I define the current in (as a Terminal).
My sticking point is how to model this perpendicular (ionic) current in COMSOL. The equation governing this ionic current will be of the form J = (1/R)*(V_electrode1 - V_electrode2); essentially the ionic current is driven by the voltage difference between each electrode. I guess it boils down to the electrodes represented as a 2D network of resistors, each connected at a node by another resistor controlling the ionic current, forming a 3D matrix of resistors.
I am confused as how to specify this ionic current. Would it be represented as a current source on the face of each electrode? I assume i would also need two Electric Current modules, one for each electrode, so that I can solve for the voltage on each one.
I feel like this is a basic problem, but I must be missing something fundamental. I appreciate any input!
Ben
3 Replies Last Post Oct 30, 2012, 3:22 p.m. EDT
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Posted:
1 decade ago
Hi
I'm not really managing to following what you are trying to do.
If you use EC (electric current), COMSOL solves for the Voltage based on your domain and boundary settings, it then derives the electric field via the gradients of V, and the current linked in via the conductivities and the electric field (+ effects of sources, charges etc) Check the equations of the EC "physics"
You can define two terminals of different voltages or currents (but that would give an even voltage or current distribnution on the terminal boundary (else use electric potential or current source BCs). But do not forget you need a GND noramlly to fix a gauge point somehwere
--
Good luck
Ivar
I'm not really managing to following what you are trying to do.
If you use EC (electric current), COMSOL solves for the Voltage based on your domain and boundary settings, it then derives the electric field via the gradients of V, and the current linked in via the conductivities and the electric field (+ effects of sources, charges etc) Check the equations of the EC "physics"
You can define two terminals of different voltages or currents (but that would give an even voltage or current distribnution on the terminal boundary (else use electric potential or current source BCs). But do not forget you need a GND noramlly to fix a gauge point somehwere
--
Good luck
Ivar
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Posted:
1 decade ago
Thanks for your reply Ivar.
Perhaps I was unclear in my explanation. Imagine that I have 2 separate rectangles on a 2-dimensional plane in COMSOL. I specify that each rectangle has a material conductivity (sigma), and that 3 out of the 4 sides of each rectangle are insulated. On the first rectangle I specify that the non-insulated edge is a Ground, and on the other rectangle, I specify the non-insulated edge as a current source.
Now, I would like to link the two rectangles electrically, such that a current would flow normal to the rectangle faces, from the current source to the ground. This current would be driven by the voltage difference developed between the rectangle faces.
Is this possible to do?
I would need to use two EC modules, one for each rectangle, so that 2 voltages are calculated, correct?
How do I specify this perpendicular current?
Thank you!!!
Ben
Perhaps I was unclear in my explanation. Imagine that I have 2 separate rectangles on a 2-dimensional plane in COMSOL. I specify that each rectangle has a material conductivity (sigma), and that 3 out of the 4 sides of each rectangle are insulated. On the first rectangle I specify that the non-insulated edge is a Ground, and on the other rectangle, I specify the non-insulated edge as a current source.
Now, I would like to link the two rectangles electrically, such that a current would flow normal to the rectangle faces, from the current source to the ground. This current would be driven by the voltage difference developed between the rectangle faces.
Is this possible to do?
I would need to use two EC modules, one for each rectangle, so that 2 voltages are calculated, correct?
How do I specify this perpendicular current?
Thank you!!!
Ben
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Posted:
1 decade ago
Hi
yes this is possible, bt you must define a air/vacuum domain covering the two electrodes and some more volume/surface around.
If you are only interested in the electric field you can use ES (electrostatics), but if you want to see current flow, you need to use EC and to give some conductivity to the "air" domain, as the resisitance from one electrode to the other and the electrode potential will define the current
Check the model library, and the model Gallery on the web, plenty to learn from there ;)
--
Good luck
Ivar
yes this is possible, bt you must define a air/vacuum domain covering the two electrodes and some more volume/surface around.
If you are only interested in the electric field you can use ES (electrostatics), but if you want to see current flow, you need to use EC and to give some conductivity to the "air" domain, as the resisitance from one electrode to the other and the electrode potential will define the current
Check the model library, and the model Gallery on the web, plenty to learn from there ;)
--
Good luck
Ivar