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-   -   getting a warning about mass imbalance in reaction (http://www.cfd-online.com/Forums/fluent/39818-getting-warning-about-mass-imbalance-reaction.html)

lily February 24, 2006 17:26

getting a warning about mass imbalance in reaction
 
I just finished looking for reaction mechanisms and was happy to really start using fluent to model. but i kept on getting the warning saying like this:"Warning: mass imbalance in reaction-1 stoichiometry." Is this normal? I cannot figure out why the reaction stoichiometry is imbalanced. Can anyone help me out here? Thanks a lot in advance.

Allan Walsh February 24, 2006 18:04

Re: getting a warning about mass imbalance in reac
 
I guess your reaction is not balanced. Check the molecular weights and stoichiometric coefficients for the reactants and products. I'm not sure how good the balance has to be, but 99%+ seems to work.

lily February 25, 2006 01:15

Re: getting a warning about mass imbalance in reac
 
thanks Allan. the reaction is as simple as c2cl4->c2cl3+cl so the stoichiometric coefficients are fine(i suppose), the molecular weight for the species are 165.83,130.38 and 35.45 respectively. but i am still getting the warning. :((

Ashish Jain February 26, 2006 01:30

Re: getting a warning about mass imbalance in reac
 
Hi Lily,

Fluent gives this warning, when the mass of two sides doesnt match. I assume u have defined volumetric kind of reaction, check u have specified correct S.F for both reactant and products and u have selected the right species from the dropdown menu.

Also check when u have defined ur species, u have assigned them correct molecular weights. I hope this will solve ur problem.

Ashish

lily February 26, 2006 09:37

Ashish, could you specify what is the s.f?
 
Thanks, Ashish. yes, i defined volumetric reaction, i checked carefully the molecular weights of the species of the reactants and products, the reaction is as simple as c2cl4->c2cl3+cl so the stoichiometric coefficients are fine(i suppose), the molecular weight for the species are 165.83,130.38 and 35.45 respectively. but i am still getting the warning. :((



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