[Marshak]

Hi!

I have a global reaction for Methane

CH4^a + 2O2^b = CO2 + 2H20

has to be calculated using the formula
R = A*T^b*exp(-Ta/T)*c(CH4)^a * c(O2)^a

In general, in the above formula, we give a constant value to reaction orders 'a' and 'b'. But I instead need to define the reaction order as follows:

a= 0.1+(0.2*exp(-700 Y_CH4)

Where Y_CH4 is the mass fraction of methane (CH4).

Does someone know how to define/write the above mentioned reaction order in the 'constant/reaction' dictionary.