forward and reverse reaction rate calculation from GRI30 mechanism

[pan....@gmail.com]

Hello, 

When we using GRI 30 mechanism, is there anyone know how the forward and reverse reaction rates are calculated? 

For example, for one reaction: 

#  Reaction 38

reaction( "H + O2 <=> O + OH",   [2.65000E+16, -0.6707, 17041])

Do we use the same reaction coefficient ( [2.65000E+16, -0.6707, 17041])  for both forward and reverse reaction rate constant calculations?  meaning that: 

rate_forwards= 2.65e16 * T ^ (-0.6707)* exp (-17041/R/T) * [H]*[O2]^2;   and rate_reverse= 2.65e16 * T ^ (-0.6707)* exp (-17041/R/T) * [O]*[OH] ????

If I want to add my own reaction mechanism, whose forward and reverse reaction coefficients are different, how can I write the reaction in the input file (such as gri30.cti)?

 

for example,reaction( "CO + 0.5O2 <=> CO2") 

rate_forwards= A1 * T ^ (n1)* exp (-E1/R/T) * [CO]^1*[O2]^0.25*[H2O]^0.5;   and rate_reverse=  A2 * T ^ (n2)* exp (-E2/R/T) * [CO2]. 

Here, the rate coefficients for forward and reverse reactions are different, and also the power dependence terms are different from specified (such as forward rate has a term of [H2O]^0.5).  If I want to add this reaction to the input file, how can I write it in the input file?  

Thank you. 

Regards,

Eric

 

[Ray Speth]

Eric,

I would suggest that you read the chapter of any book on combustion that covers gas phase kinetics to understand the way that this is done and why. Normally, the reverse rate is calculated based on thermodynamic considerations using the equilibrium constant. If you specify your own value for the reverse rate constant, then a mixture at equilibrium will not have equal forward and reverse rates, which makes no physical sense.

Regards,

Ray

[Manoj Kumar]

see this link it will be helpful
http://c3.nuigalway.ie/software.html

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