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.

Calculate heat transfer coefficient

Please login with a confirmed email address before reporting spam

I want to model air flow past a helical coil with heat transfer, and I need to characterise the local heat transfer coefficient between the heated coil and the flowing air.

I cannot use a known relation since the geometry is complicated, so I need to find the resulting flux and then calculate h from flux = hA(T-Tinf).

However, if I find convective heat flux at a surface (ht.cfluxMag) (Results>Export>Data>Dataset:surface) , that seems to be the flux in the air medium rather than through the solid-air boundary, since it depends on the wind speed at the surface. I need the flux across the surface.

From www.comsol.com/blogs/calculating-the-heat-transfer-coefficient-for-flat-and-corrugated-plates/ it says "From the simulation results, it is possible to evaluate the heat flux using the corresponding predefined postprocessing variable." but it is not clear which predefined postprocessing variable they are referring to, since it is not ht.cfluxMag.

Is there a built-in function to calculate the flux through a boundary, or do I have to calculate it from other variables (eg. temperature at first grid node near boundary)?

I aim to set boundary condition at the coil of constant temperature and solve for the flux due to the air flow.

Tl;dr: How to find heat transfer coefficient by calculating heat flux through a boundary


0 Replies Last Post 3 giu 2021, 09:37 GMT-4
COMSOL Moderator

Hello XQ Sun

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.