Learning Forum

[dmr011]

I'm trying to simulate an electrochemical reaction along with the hydrodynamics of the cell. I am using the electrochemical reaction setup in Ansys Fluent, to initially perform water splitting reactions on the anode and cathode.

The issue I am having is that I getting the following error when running the first time step and this seems to cause the calculations to diverge. "Faradaic current solution failed at Thread id: 1745" where 1745 corresponds to the surface of the electrode. What might be causing this error. Residuals for the products and the continuity equation as well as potential spike shortly after starting the iterations. 

I'm also confused about the definition of the potential at the boundaries and for the reactions. I assume the equilibrium potential in the Butler Volmer reaction kinetics is the same as the half cell potential for the reaction also used in electrochemistry. But how does the potential we define for the boundary condition on the electrode relate to this? Is the potential we define for the boundary condition the absolute potential at the surface, or is it the potential relative to the reaction we define there? When I define a potential at each electrode, does this mean that the potential gradient between them is the difference between these two potentials, or is it from the difference between these potentials and the equilibrium potentials of each electrode reaction?