CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CFX (
-   -   Specifying a chemical reaction (

hagupta March 20, 2006 09:33

Specifying a chemical reaction

I have a single "Variable composition mixture". It has 5 components - 4 gases and 1 solid. Out of these, the solid and a gas are formed after the user-defined chemical reaction.

The problem is that when I go to the Domain settings, this reaction is not displayed in the Combustion/Reaction Models drop down menu. As a result, I am unable to include the reaction modelling in my problem.

The help files state that "variable composition mixture" or "reacting mixture" can be used for reaction modelling.

Thank you in anticipation, hagupta

opaque March 20, 2006 09:55

Re: Specifying a chemical reaction
Dear Hagupta,

After you setup the reacting mixture, you only have to set the Combustion Model.. The user-defined chemical reaction is implied by the mixture definition..

Did you use your used-defined reaction to create the reacting mixture? If you did, you are ready to go... Check that the COMPONENT option are properly set to either Transport Equation/Library or Constraint as appropriate for your case..

Good luck, Opaque

hagupta March 21, 2006 05:25

Re: Specifying a chemical reaction
Thanks for the reply,opaque.

I was trying to set up the reaction using Variable composition mixture. Anyways, now I have changed to reacting mixture and it seems that there are no problems.

Could you guide me regarding the "Thermodynamic State" option in the Reacting mixture setup. My reacting mixture contains 4 gases and 1 solid. So, is it ok to set this option to gas??

Also, for the chemical reaction involving a solid product, is it necessary to switch on the "Particle Tracking" option?

Joe March 22, 2006 02:46

Re: Specifying a chemical reaction
It is possible to model a dust as a gas with a large molecular weight. In some situations this model may give good results. However you regard your flow as single phase with this approach.

Multiphase is also possible. Look at cases with oil or coal as fuel. You should find examples there how to do it with multiphase.

All times are GMT -4. The time now is 03:23.