To model pre-mixed combustion, has anybody used the laminar finite rate model?

I have a few questions about this. Id appreciate it very much if anybody could help me out on this.

Thanks and Regards, Shankar.

What are your questions?

Hi

What will be the unit of A when E is in j/kg mol and other values are in SI units? ( k= A T^n exp (-E/RT) )

If you used the default reactions from the FLUENT database, do you have any idea how A and E were calculated?

I also do not understand how the value of the rate exponent was set?

Most of the literature found have the units of A and E as cm3 mol s and kJ/mol. Did you define your own reactions?

Thanks, Shankar.

> What will be the unit of A when E is in j/kg
: mol and other values are in SI units?

The units of A depend on the reaction: the Arrhenius reaction rate is governed by the product of the species concentrations to certain powers. So, the units of A are different for each reaction.

When converting from cgs units (eg CHEMKIN) to SI (eg Fluent), you can use

A(SI) = A(cgs) * 0.001^(sum_exp-1)

where sum_exo is the sum of the rate exponents

> If you used the default reactions from
: the FLUENT database, do you have any idea
: how A and E were calculated?

Most of these came from:

Westbrook, C.K. and Dryer F.L., (1981) "Simplified Reaction Mechanisms for the Oxidation of Hydrocarbon Fuels in Flames" CST, 27, pp.31-43

> Most of the literature found have the units
: of A and E as cm3 mol s and kJ/mol. Did you
: define your own reactions?

Fluent can import mechanisms in Chemkin format.

Thanks for your reply. I will go through your references.

Shankar.