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-   -   heat of reaction (http://www.cfd-online.com/Forums/fluent/31902-heat-reaction.html)

Paul July 29, 2003 15:45

heat of reaction
 
Hi

I am trying to simulate an endothermic reaction using the species model in fluent. I am using the volumetric reaction model(finite rate).Is it possible to use this model for reactions other than flames etc? Is there any way I can assign a -ve heat of reaction for the reaction in fluent?

Thanks


Erwin July 30, 2003 08:07

Re: heat of reaction
 
Assuming that -ve means 'negative', yes. You can model various types of both endothermic and exothermic reactions.

Paul July 30, 2003 12:01

Re: heat of reaction
 
Hi Erwin

Thanks for the reply. I meant 'negative' with the sign '-ve'. As I mentioned in the previous message that I am using the volumetric reaction model in Fluent to solve for species transport. I have gone through the fluent manual for this model but I am not quite sure how is the heat of reaction handled in fluent. I would be glad if you could advice me regarding that.

thanks

Erwin July 31, 2003 08:00

Re: heat of reaction
 
The heat of reaction is the result of the difference in enthalpy between reactants and products of a chemical reaction. So for example methane and air have an enthalpy x before the reaction, flue gas has an enthalpy y after the reaction. The difference is heat of reaction. Simple.

Paul August 7, 2003 11:58

Re: heat of reaction
 
Hi

Thanks for the help. I was able to figure out that part as it very much is the definition of heat of reaction. My problem is a bit different than that. First I am trying to model the motion of a granular bed inside a rotating clyinder by approximating the bed as a fluid and fitting a velocity profile to it. However the problem arises when i am trying to model the reaction inside the bed...for which i am getting absurd results...so for that reason I wanted to know how exactly does fluent handle source term in the energy equation. Also the results are sensitive to the mass diffusvity but reaction bascially is in the solid phase(thermal decompsition of calcium carbonate ) its hard to define the mass diffusivity for such a system.The reaction model in fluent seems to be defined more for combustion models. Please let me know if its feasible to model such a reaction using fluent and if so what approcah has to be taken.

Manan


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