Learning Forum

[mehmood.khizerme]

Hi,

I have been using Ansys fluent for quite sometime and now its my first time trying to simulate the planar geometry SOEC using the SOFC Unresolved Electrolyte module. Its been a month that I have been facing issues in setting up the boundary conditions correctly. I have gone through the manual and its been of a great help but still the problem persists.

The problem is that there is no electrochemical reaction happening inside and the species remain as it is, as it is defined at the inlet.

To be specific I am having issues while selecting the accurate voltage and current tap surfaces, i have got an option of series of walls and interfaces, i have done multiple hit and trial method with data from different sources available on the internet but its of no use

Secondly i want to know if i have to individually set the electrical boundary condition for different interfaces in the BC task page or is it enough to specify the system voltage in the SOFC Model parameters tab.

Lastly, in the cell zone conditions i need to specify the porosity for cathode and anode but the porosity tab is only available if i opt the them to be fluid and not solid.

[Vijay Narayan]

Hi,

May i know your reasons to use SOFC w/ unresolved electrolyte to model SOEC ? Since there exists an option to model SOEC within Fuel cell and ELectrolysis module (by selecing electrolysis choice) as outlined in the Theory Guide. Could you share snippets from the Fluent GUI with regards to your other sub queries so that I understand your issues correctly.

For the last question, Cathode and Anode are modelled as Solids hence specification of Porosity definition is not available (i will confirm and update in this Forum response in a few days).

Thanks

[mehmood.khizerme]

Hello Vijay,

I had to do some model valdations for my reserach thats wht I opted for the SSOFC Unresolved Electrolyte model.

Now the issue is that in the literature SOEC has components like anode, cathode, anode and cathode current collectors specified as porous and the flow channels and current collectors are same (flow channel and CC are specified as same porous media, steam flow channel/An-CC = porous nickel and air flow channel/Ca-CC = stainless steel) 

I have followed all the Fluent User Guide, Theory Guide and Tutorials but still no desirable results as none of the the guides tackles the issues regarding the porous media for the SOFC Unresolved Electrolyte model

[Vijay Narayan]

Hi,

I checked internally and below are the responses:

a) The anode and cathode which you are referring to are the porous electrodes. These have to be defined as Fluid zones to have the porosity specification. Current collectors will be solid domain and cannot be specified as fluids. (This specification is same for all the Fuel cell modules)

b) You can specify the voltage or current in the Model parameters tab. This is sufficient and you dont have to specify the details at the BC explicitly for the terminals. Care should be taken to ensure the gas channels are specified the correct species to model the SOEC as against a SOFC system.

Regards

[mehmood.khizerme]

Hi Vijay,

The thing is that I have defined the Collector materials as solid and my study involves a corrugated collector sandwiched between the interconnect and electrode (cathode and anode) in the fluid domain, so to cater this I have defined the fluid domain as porous media with high porosity in the flow direction, The fluid domain both the steam and air flow channels have SOFC mixture as the fluid material and the anode collector and cathode collector as solid materials respectively for the study.  

So is my approach appropriate as per your trailing reply that collectors need to be solid?