Opaque - Thermal Radiation
 

Hai all,

I am doing a Fluid Solid CHT simulation. I have divided my fluid domain into different domains (one that is in contact with farfield boundaries and one that is in contact with solid regions) for simplicity. There are Fluid Fluid interfaces between these domains. I have set a Thermal Radiation Model to those Fluid domains which have the farfield boundary and I have set a Thermal Radiation BC to the farfield boundaries.

In this case, the Fluid Fluid interfaces become compulsarily opaque for Thermal Radiation. Is this right?

Or should I set the Fluid domain which have contact with the solid regions also to Thermal Radiation model and the Fluid Fluid interfaces to conservative interface flux?

Thank you.

Regards,

Subha.

Re: Opaque - Thermal Radiation
 

Dear Subha,

Why would a Fluid Fluid interface be opaque? Does the domain interface try to represent some non-meshable surface? or is it just a "virtual modeling artifact". For the latter, the only physical BC is Conservative Interface Flux.

For the case that the domain interface represents a infinitely thin surface that is not represented in the mesh, but that can change the radiation field considerably (guess a very thin screen with special radiative properties), the issue becomes more complex. I would advice to contact CFX support an explains the details.

Opaque.

Re: Opaque - Thermal Radiation
 

Hai Opaque,

The interface is only a simple wall dividing the domain and so it cannnot be a non-meshable surface. I use a Conservative interface flux on the interface.

Regards,

Subha.

Re: Opaque - Thermal Radiation
 

hi Subha, i recommend to you to leave fluid/fluid interfaces as conservative interface flux, unless you have different fluid materials among them. Radiation properties are important in fluid-solid interfaces. If that fluid/fluid interface is representing a wall, you can set radiative properties there.