Learning Forum

[Srieder]

Hi, I'm working on a simulation of a electrochemical cell.

At the moment I'm working on a very basic simulation which is simplifying the electrolysis to a electric problem. Therefore I created a cuboid with the electric properties of an electrolyte (0,008m³ and 3 smaller cuboids with the electric properties of steel electrodes (160mm³. I placed the electrodes in cavities in the electrolyte. The electrolyte cuboid is that much bigger to ensure no affect of it on the current flow. On one electrode (auxiliary electrode) I applied constant 200V on the outter surface. On the second electrode (working electrode) I applied constant 0V. The last electrode is without any use at the moment. I would expect a current to flow between the surface of the two surfaces without any current flowing out of the system at any other surface. The results I get leave me confuesed. The currents flowing over the surface of the auxiliary and the working electrode are extremly high with about 700kA. Furthermore there is also a current flowing outside of the system at every other surface of the problem. This holds true even if i apply boundary conditions on every of those surfaces with 0A. Can anyone help me with the interpretation of these results?

The final goal ist to have simulation of system with a auxiliary, a reference and a working electrode. To make any use of this 3 electrode arrangement I would need to simulate the potential resulting from chemical interaction between the electrodes and the electrolyte. Does somebody have expertise on the simulation of electrolysis and can give me any tips regarding this topic?

 

Thank you very much for any help! I remain very confused at the moment and don't know how to move on.

Sascha

[Srieder]

Perhaps the problem I presented was to big and general to get an answer. I have a very simple problem at the moment which I dont understand. I created a rectangular steel bar. On their ends I applied 10V respectively 0V. As expected their is a constant current flow between the two planes in y-direction as to be seen on the image. The magnitude is due to the fact that the steel bar provides only a low resistance. What I don't understand is the current flow in the other 2 directions, x- and  z-direction (z-direction on the image). The magnitude is very small in comparison to the one of the y-direction, still it should be 0. One possible reason could be that it's an error due to the numerical calculation. Can someone confirm this? 

 

I also tried to apply a boundary condition of 0 A on the 4 planes I don't expect current to flow through. This caused the following error:

Can someone explain to why there is a different condition to the adjacent entities? 2 planes with applied voltages and 4 planes perpendicular to them with applied current conditions seem fine to me.

 

Thank you for any help!!