[alireza2475]

hi guys,

I'm trying to use UDS to model the fire product (CO2, CO, Soot,...) propagation in a duct-like geometry which has some complex curvature in its section.
The problem arises when I model the thickness of the walls (solid zone) to consider the conduction heat transfer in them. either by adding a solid zone having the correct thickness outside the walls in gambit or enabling shell conduction zone in the Fluent, I encounter the same problem. The UDS equation in single core solution leads to invalid number residual and in multi-core on single CPU it shows an error box showing "floating point error: invalid number". By the Way, not considering the solid zones, the problem disappears.

The scalars are solved in fluid zones only and the flux function is based on "mass flow rate". the scalars have a source term in an internal fluid zone.

Does any body have any idea regarding solving the problem. thank you very much guys.

[alireza2475]

Is there any comment on the above issue? I'm still confused with the problem!

[A CFD free user]

Hi!
Maybe you forgot to set the scalar for solid zone as well. Go to define/user defined scalar/ and from solution zone drop down list, select appropriate solid zones for the interested scalar too.