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Gang March 10, 2003 10:56

modeling procedure
 
I am trying to model sofc temperature distribution. my overall procedure by using Fluent is: 1. use surface reaction to treat cathode reaction: O2->2O

and Anode reaction H2+2O->H2O. In this step ignore the heat generated by electrical part, like ohmic loss.

2. Add electro potential by using user defined scalar.

3. Add heat radiation.

Now I am checked by step one. Because it looks that Fluent can not treat O as the surface species. Then there is no reaction there. How can I tell Fluent that O can be traveled through the solid wall- electrolyte?

Thank you so much! Any suggestions will be highly appreciated!\

GAng

Murali March 10, 2003 18:41

Re: modeling procedure
 
<font face = "courier new">gang:

Is your question as follows ?

"O2---> 2O is the reaction. Happens at the surface of the cathode-electrolyte interface. The product O can squeeze through the solid wall and appear else where." ?

Murali </font>

gang March 10, 2003 21:12

Re: modeling procedure
 
Yes, exactly!

Murali March 12, 2003 13:59

Re: modeling procedure
 
<font face = "courier new">This problem can be tackled using the DEFINE_SOURCE udf. The surface where this reaction is happening will have a set of (computational)cells attached. Call this set "A". Similarly the "O" can squeeze through,i.e, it travels through the solid and reappears at another set of cells. Name these cells set "B". Presuming that you are NOT solving for the diffusion of O in the solid cells, the best way to model this is by applying two source terms in A and B which are numerically equal but differ in signs. The rate of "production" of O at the surface A would be known throuh kinetic expressions. This "rate of producion" shoudl be applied as rate of disappearance in cell set B. This way you can solve the problem. Refer to DEFINE_SOURCE</font>


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