Learning Forum

[afoster]

I'm working on a model correlation and it occurred to me that a relatively simple feature could be added to Thermal Desktop that would make my correlation much simpler. The feature would be radiative area multipliers. They would work like conductivity or density multipliers, but they would scale the calculated radiative area of the elements in the surface of interest so that you could increase or decrease how much a surface radiates without adjusting optical properties (especially because you can't go above 1 for optical properties) and without having to adjust geometry.

Does anyone know if this feature already exists in some way I'm not aware in Thermal Desktop? Thanks.

[Doug Bell]

That wouldn't work for radiation calculations since the area would change not only the Bijs and Bjis (gray-body exchange factors) for the surface itself but also for any reflections off of that surface.

If you simplify your system such that the surface in question only views space, you can leave it out of the radiation calculations (ray tracing) and create a radiation node to surface conductor between the surface and the space node (create a boundary node names SPACE.1). With that, you can modify the radk value, which is Area*emissivity*Bij. That can be easily modified without affecting other calculations or without modifying your surface dimensions.

Let me know if you found this helpful or have other questions or concerns.

Kind regards,

Doug