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-   -   CFX and Chemkin file (http://www.cfd-online.com/Forums/cfx/68692-cfx-chemkin-file.html)

Margherita September 29, 2009 05:22

CFX and Chemkin file
 
Hi!

I woud like use a Chemkin reaction mechanism in a CFX combustion simulation.

Is it possible to import in CFX a file from chemkin?
How I have to do to import Chemkin files?

Thanks a lot for your help!!! :)

Margherita

ckleanth September 30, 2009 19:33

No only if you have the kinetic rates for a specified combustion process. I assume you can use chemikn to obtain the kinetic rates however I have not done this so this is just a guess.

chemkin models the kinetics excreted between molecules. the majority of combustion models in cfx assume that reactions happen instantaneously at the molecular level and progress with a given reaction rate. there are some reaction rates for common chemistry however you may be use your own reaction rates based from experiments, papers etc. there is another combustion model called flamelet model and is based on a non premixed combustion process that describes the interaction of chemistry with turbulence. I have yet to used this combustion model, however I have recently seen a post that someone had described it a bit better. bear in mind it that to create your own flamelet library it require cfx-rif which in turn is an add-on to cfx and requires the purchase of an additional license .

alpha754293 May 2, 2012 16:58

Quote:

Originally Posted by ckleanth (Post 231060)
No only if you have the kinetic rates for a specified combustion process. I assume you can use chemikn to obtain the kinetic rates however I have not done this so this is just a guess.

chemkin models the kinetics excreted between molecules. the majority of combustion models in cfx assume that reactions happen instantaneously at the molecular level and progress with a given reaction rate. there are some reaction rates for common chemistry however you may be use your own reaction rates based from experiments, papers etc. there is another combustion model called flamelet model and is based on a non premixed combustion process that describes the interaction of chemistry with turbulence. I have yet to used this combustion model, however I have recently seen a post that someone had described it a bit better. bear in mind it that to create your own flamelet library it require cfx-rif which in turn is an add-on to cfx and requires the purchase of an additional license .


Quick question then - does that mean that the flamelet library (FLL) files and the representative interactive flamelet (RIF) files/tables do actually solve for the kinetics during the CFD solution process - and it just does what effectively amounts to glorified table lookup?

(Please correct me if I'm wrong - I've read the manuals and it doesn't really state).

I'm trying to model a spark ignition (SI) internal combustion using the spark ignition model (BVM), and also using the gasoline RIF to calculate the energy release due to combustion.

Am I on the right track or am I totally doing it wrong and that there is another better way of getting at it?

I've also noticed that using the BVM/RIF, flame density isn't an output variable, which is why I am suspecting that it doesn't actually calculate the burn; but rather interpolates based on tables.

Any help would be greatly appreciated.


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