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-   -   Setting up reaction parameters for a 3-step oxidation mechanism of C3H8 (http://www.cfd-online.com/Forums/openfoam/84036-setting-up-reaction-parameters-3-step-oxidation-mechanism-c3h8.html)

 jose_rodrig January 18, 2011 15:06

Setting up reaction parameters for a 3-step oxidation mechanism of C3H8

Hi

I intend to simulate the oxidation of propane in a combustion chamber with a 3-step mechanism:

C3H8 + 1.5 O2 = 3 CO + 4 H2

CO + 0.5 O2 = CO2

H2 + 0.5 O2 = H2O

For that I ll use reactingFoam solver and the built-in chemistryReader of OpenFOAM.

So, in order to setup the reaction kinetics and mechanism in the reactions dict, I look up in the literature and found out the mechanisms and parameters proposed by Westbrook and Dryer (1981b)

Unfortunately, this mechanism takes into account 2 extra parameters other than activation energy, beta and the frequency factor. In fact, he proposes the following equation:

R = A exp( -Ea/(RT) ) [A]^a [B]^b , with beta=0

Questions:
A. Is there any reaction type library that might account for this extra parameters? (in contrast with irreversibleArrheniusReaction that accounts only A, beta and Ea).

B. If the answer to A. is negative, can somebody point the file in the source that calculates the reaction rate, so one can try to modify it?

Thank you in advance!
Jose

 kalle January 19, 2011 03:56

Hi!

I know that the chemkin reader also available in OpenFOAM handles this. Have a look in the aachenbomb tutorial, specifically the chemkin/chem.inp-file, where parameters a and b are represented with the FORD keyword. I used westbrook and dryers mechanism with the chemkin lexer in OF without problems.

Good luck!
K

 sahm January 28, 2011 02:49

Reaction File

Hi, Could You please send me your 3 step Propane reaction file?
you can send it to my email or upload it here.

 mo.houssami February 4, 2014 14:25

similar problem

Hello,

I am trying to do something similar but with a 2 step mechanism.
reactions file is fine, but I can't figure out what to put in constant/thermophysicalProperties. :confused:

For a single step, I was using the following:

thermoType hsPsiMixtureThermo<singleStepReactingMixture<gasTh ermoPhysics>>;
inertSpecie N2;
fuel CO;

How should I adapt it to add a second reaction with CH4 as the second fuel?

Thank you

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