Learning Forum

[Rania Saad]

hi, I'm modeling a single cell with an area of 50cm² and with 5 path serpentine flow fields. I followed the ansys tutorial for 3D meshing part and have a hex meshin in the active zone with an orthogonal quality of 1. And for the bipolar plates and flow fields with polyhedra meshing got 0.2 for orthogonal quality. Now the problem is in fuent. I have tried every recommendation out there and did a ton of trys but no sucess. I still can't make it converge. It either diverge because of uds3 or temperature. It either diverge as soon as I turn on electrochemistry sources in pem models. Or after a couple (sometimes after 100 iterations). Could someone please recommend me a solution to try. Thank you

[John Ibrahim]

Hello Rania,

It is hard for me to judge what is going one.  However, my recommendation is to try one of the tutorial by building it from scratch and see if you miss anything.  Also you could use one of the tutorial geometries and use your own flow operating conditions to see if the model converge.  You may need to scale the geometry if needed to have a resonable matched conditions.  By doing so, you may be able to get an idea what could be wrong.

Also you could try the transient solver with small time step and observe the change in the temperature.  Make sure you have conformal mesh so the cell zones are connection.  Additionally you may well under relax the potential to see if this help.

Best,

John