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Physical significance and units of Cathode boundary condition in Primary current distribution calculations

Posted 9 nov. 2015, 13:40 UTC−5 Electrochemistry 3 Replies

Palli Srinivas
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In the primary current distribution calculations, the Electrolyte-Electrode Boundary Interface boundary condition [Eq. surface integral of local current densities]is used at the cathode surface. What is the physical significance of this boundary condition? The units of this boundary condition are not consistent. Is the form of this boundary condition is correct or wrong? Please give me answers as soon as possible.
3 Replies Last Post 10 nov. 2015, 09:14 UTC−5
Lasse Murtomäki
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Posted: 9 years ago 9 nov. 2015, 14:43 UTC−5
You can control potential or current between the electrodes. Current boundary condition means that you define the current you are drawing out of the cell. Because the primary current distribution is about the the effect of the cell geometry, the local current density varies along the electrode, but the the total current is the one you define.

How do you mean the units are not consistent?

BR
Lasse
You can control potential or current between the electrodes. Current boundary condition means that you define the current you are drawing out of the cell. Because the primary current distribution is about the the effect of the cell geometry, the local current density varies along the electrode, but the the total current is the one you define. How do you mean the units are not consistent? BR Lasse
Palli Srinivas
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Posted: 9 years ago 10 nov. 2015, 08:33 UTC−5
Thank You very much Lasse Murtomäki for reply.

In reply, whatever you said is correct. But, the boundary condition equation is surface integral of n.il (where n is the normal vector, pointing out of the domain and il (A/m2) is the electrolyte current density vector) which gives us an applied average current density. The units of left side of the equation is not equal to the units of the right side of the equation i.e. (A/m2). Is this equation correct or any quantity in that equation is missed. Please clarify me.



Thank You very much Lasse Murtomäki for reply. In reply, whatever you said is correct. But, the boundary condition equation is surface integral of n.il (where n is the normal vector, pointing out of the domain and il (A/m2) is the electrolyte current density vector) which gives us an applied average current density. The units of left side of the equation is not equal to the units of the right side of the equation i.e. (A/m2). Is this equation correct or any quantity in that equation is missed. Please clarify me.
Lasse Murtomäki
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Posted: 9 years ago 10 nov. 2015, 09:14 UTC−5
OK, you are using the average current density BC in 2D; then it should be, indeed, A/m. This could be a bug. In a 3D model units are correct. Yet, I do not believe this has any significance.

BR
Lasse
OK, you are using the average current density BC in 2D; then it should be, indeed, A/m. This could be a bug. In a 3D model units are correct. Yet, I do not believe this has any significance. BR Lasse

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