CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Primitive Error at Node (

Deb January 5, 2009 01:45

Primitive Error at Node

I am trying to do a combustion model using ARM-19 mechanism which is inbuilt in fluent. I am ISAT for the species integration. It ends up with the following msg.

Primitive Error at Node 1: ISAT reaction rate: Temperature = -1347.3K

Though I tried to change the URFs for the species equation and energy equation and change the pressure-velocity coupling from segregated to coupled it ends up with same. Can anybody let me know the posiible reasons.

Thanks Deb

sescobar December 9, 2011 13:07

Primitive Error at Node : ISAT reaction rate: Temperature
Although this was a while ago I will share my experience.
I was encountered the same problem, and it turned out to be that i was using kinetic-theory to calculate the specific heat of the species in the mechanism instead of using the polynomials given in the thermodynamic properties data base. So far it seems to be working fine.

Basy December 12, 2011 04:33

hi dear sescobar
Would you please mention the model in which you faced this problem? I guess you were using EDC right? because I am facing same problem with Steady Laminar Flamelet and I find no place in material properties panel where I can change Cp calculation method form say, kinetic-theory to polynomial...

So would you please explain more about the model you used?

Thank you
behzad :)

All times are GMT -4. The time now is 17:16.