# Premixed combustion -Laminar finite rate model

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 March 16, 2004, 16:39 Premixed combustion -Laminar finite rate model #1 Shankar Guest   Posts: n/a 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.

 March 16, 2004, 17:10 Re: Premixed combustion -Laminar finite rate model #2 cg Guest   Posts: n/a What are your questions?

 March 16, 2004, 17:19 Re: Premixed combustion -Laminar finite rate model #3 Shankar Guest   Posts: n/a 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.

 March 16, 2004, 22:03 Re: Premixed combustion -Laminar finite rate model #4 cg Guest   Posts: n/a > 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.

 March 17, 2004, 15:32 Re: Premixed combustion -Laminar finite rate model #5 Shankar Guest   Posts: n/a Thanks for your reply. I will go through your references. Shankar.