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 The information provided may be out of date.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.

boundary condition of solar radiation

Please login with a confirmed email address before reporting spam

hi...
I have some question about solar radiation model (external radiation source)
Applies to the wall of building, only one side of wall is applied the solar incident radiation.
I was modeling the wall as 2D (rectangle wall)
How should I set the boundary conditon of wall

1. only one side of wall ( solar incident radiation)
surface-surface radiation? or surface-ambient radiation?

2. others of wall
adiabatic? or surface-surface radiation? or surface-ambient radiation?

my geometry is in attached file


1 Reply Last Post 26 juin 2012, 02:32 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 26 juin 2012, 02:32 UTC−4
Hi

the best is to check each one, read the help and look at the equations:
Heat flux gives an incident boundary (surface) flux in W/m^2 with some options
Convective cooling corresponds to the removal of heat by air convection (not that much different from the previous, but it "bins-in" the internal variables convection part)
Surface to ambient is for radiative exchange to a large outside domain at a given temperature
Inflow heat flux mimics a virtual domain

For solar flux, if I read the new 4.3 doc correctly you must turn on the surface to surface or re radiating surface check box this will add new items in the right-click list (was probably the case in 4.2 too )


--
Good luck
Ivar
Hi the best is to check each one, read the help and look at the equations: Heat flux gives an incident boundary (surface) flux in W/m^2 with some options Convective cooling corresponds to the removal of heat by air convection (not that much different from the previous, but it "bins-in" the internal variables convection part) Surface to ambient is for radiative exchange to a large outside domain at a given temperature Inflow heat flux mimics a virtual domain For solar flux, if I read the new 4.3 doc correctly you must turn on the surface to surface or re radiating surface check box this will add new items in the right-click list (was probably the case in 4.2 too ) -- Good luck Ivar

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.