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-   -   SOFC temp. dependant i_o (http://www.cfd-online.com/Forums/main/123831-sofc-temp-dependant-i_o.html)

SOFC September 22, 2013 08:40

SOFC temp. dependant i_o
 
Hi

I am currently working with the SOFC unresolved electrolyte addon-module. From what can be seen in the "Activation Parameters" window, the temperature dependant exchange current density is the same for the anode and cathode, as you can only define one constant A and one constant B. The equation is as follows:

i_o=A*exp(-1/(BT))

Theoretically, and due to the -very- different materials used for cathode and anode, four constants should be defined (2 A's and 2 B's). My two questions are:

1. When the temp. dep. I_o equation is being used, the values written in "Constant Exchange Current Densities" are useless, right?

2. Would it be easy to define two constants A and two constants B modifying the consit.c file? If yes, usually the parameter A is not a constant but temperature dependent too (A= Constant*T). Would it be possible to make it temp. dependent?


Thanks beforehand!

Schluckner March 25, 2014 05:52

Hello,

I am facing a very similar problem! I am using the SOFC with unresolved electrolyte Module.

I was wondering if you still use the temperature dependant correlation for i_0 ?
In order to fit my simulation results to experimental data it would be necessary to make the anode exchange current density temperature dependant.
Unfortunately the calculated values for coeff. A and B won´t deliver the results as expected.
The c-file (constit.c) states, that if the temperature dependant i_0 is enabled, the above mentioned exponential correlation should be used.
Various simulations showed, that the values set for constant anode and cathode exch. curr. density still influence the calculated cell voltage.

So, my question is, if you were able to figure out a solution for your problem ? In the c-file it seems to me, that the temp. dependant i_0 is linked to the cathodic reaction, because the if-query combines the int-variable "temperature dependant i_0" and an equation called "Eq_O2", which indicates the cathodic reaction.

Best regards,

C.

manikanta January 6, 2015 01:27

facing problem in specifying activation energy
 
hi guys i am beginner in ansys fluent, i am facing problem in specifying activation energy, there is no particular information available on activation energy in ansys fluent tutorial of fuel cell, please guys if possible send me the procedure from beginning
my mail id is manikantadevarmani@gmail.com
if possible send video of the procedure

thanks a lot advance


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