Judy Cooper
Ansys Employee


Hi David:

Does the divergence for the multiphase case with electrochemistry occur in both 2022R1 and 2022R2?

The error you are getting can occur when the elextrochemical reactions are occurring too quickly or when they are being driven in the wrong direction by external conditions, such as imposed boundary conditions, or divergence. This can happen if the reaction rates are set up incorrectly, or if the timestep is too large. (Timesteps of 1.0e-04 s may be required to start off cases until the species stabilize.)

When the electrochemistry model only operates in one phase, the only interaction between the electrochemistry framework and the gas phase will occur at the phase interface, where heat and possibly momentum transfer occurs.  (I am assuming that there is no  interphase mass transfer?)  The phase boundary can therefore affect the reaction rates if excess heat is removed or transferred.

What is the role of the gas phase in this analysis?  Is it transferring heat to or from the liquid (electrolyte) phase? Is the electrolyte phase flowing or stationary?  Are your phases setup so that the species are in the solved (primary) phase?

If you can send screenshots of both your reactions and their electrochemical rate setup, this will be helpful.  Please note that a reference concentration is required for any specie on which the reaction rate(s) are dependent. Reference species concentrations default to zero, which can lead to infinite or zero reaction rate for rate-determining species.

Best Regards,