Global Mechanism Configuration
 

hello
I am simulating combustion using SAGE fully-detailed chemistry. I need to use a global mechanism with 3 steps (2 reaction). Usually we need to declare the exponent of the different substances in each reactions manually, when using global mechanism. Does anyone know how I can declare this in CONVERGE? Thanks for your time helping me.

Hi Amir,

Thanks for asking about this. Could you please post a screenshot of the reactions and/or mech.dat here? That would help us answer the question!

Regards,
Karan Bansal

Hi Karan,
This is a global mechanism for CH4 with 2 reactions and three steps, provided with forward reaction rates. Every thing about reactions are known in the paper. However, I do not know how to declare the exponents in the reactions for each substances. Thanks for your time.

Hi Amir,

In CONVERGE we specify the Arrhenius coefficients in mech.dat file. We can supply the pre-exponential factor, the temperature exponent and the activation energy for all reactions via this file. Please look at some of our engine combustion example cases available in Studio to see sample mech.dat files.

If you still have problems generating the mech.dat, please send us an email at support@convergecfd.com using your official email and we will help you out.

Thanks,

How can I input the power for each species in arenhuis formula in Converge. I need this to use the global mechanism. I need to know how converge deals with the global mechanism. Because every global mechanism you see on the papers, there is a specific information about the powers of mass fraction of the reactants for the golbal reactions. I need to know how I can input that in converge. Thanks

Hi Amir,

The format you are looking for is the "Fractional Order (FORD) Reaction Option". This is explained in the v2.4 CONVERGE theory manual. This format allows you to modify the stoichiometric coefficients for global reactions.

Thanks,

Hi Sameera
Thanks you very much for your response. I am using Converge 2.2.0. Do you know whether this Fraction Order Option is available on this version? Since I tried several times using FORD lines (using like this /SPECIES FRACTION/) but it seems the line can not be interpreted in that way.
Thanks
Amir

Hi Amir,

Yes, this is in v2.2 as well. Please see section 9.1.5.6 in the v2.2 theory manual.

Thanks,