Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Coupling Surface-to-Surface Radiation and Rad. in Participating Media

Please login with a confirmed email address before reporting spam

Hello,

My problem contains both radiation types: a glass-like solid cylinder with an absorption coefficient is
surrounded by a transparent noble gas within an cylindrical enclosure that has a known temperature
distribution. Every item of the problem is rotationally symmetric, however, I use 3D in order to use
COMSOLs Radiation capabilities.

In the model setting I have used for 'Add Physics'
# Heat Transfer with Surface-to-Surface Radiation (ht)
but have activated the Physical-Model-boxes for both
- Surface-to-Surface Radiation and
- Radiation in Participating Media (no scattering, only absorption)

When disabeling 'Radiation in Participating Media' the results seem reasonable, i.e. the temperature
on top of the cylinder is rotationally symmetric and somewhere inbetween the lowest and highest value
of the boundary temperatures.

However, when including Radiation in Participating Media, the temperature has cold spots along the
periphery every 90 degree. In case of low absorption, the temperature on top of the cylinder has even colder spots than the coldest value at the boundary: totally strange!

Changing parameters (discret: S4 to S6 to S8) has slightly improved the result but not solved the problem.
No effect by finer grid or changing from linear to quadratic discretisation.

Can anybody recommend to me some modification of my settings??
Does anybody know about a demo-example? The ones in the Model library are single problem tasks.

Thanks in advance,
Klaus Boettcher

0 Replies Last Post 18 juil. 2013, 05:15 UTC−4
COMSOL Moderator

Hello Klaus Boettcher

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.