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.

How to apply Heat Transfer Coefficient

Please login with a confirmed email address before reporting spam

Dear COMSOLers,

In the attached "simplifed" 3D model I am studying the thermo-mechanical behavior of a system composed of: a- a graphite block (represents beam dump in reality) heated with some volumertic heat source (represents heat deposited in the beam dump fromhadronic beam in reality). b- a side cooling Cu heat sink plate that is in a contact with the graphite block. The heat removal between these two bodies is governed by a "Thermal Contact" BC at the interface between them. c- water cooling tubes inside the bulk of the heat sink plate. The heat removal between these two bodies should be governed by the heat transfer coefficient, h, at the interfance between them.

While all BC values applied here are arbitrary, in real model, all values are carefully estimated, and the h was estimated using Nusselt number(Pr,Re).

The problem is that, using geometry "Form Union" I am not able to apply the heat transfer coefficient on the boundaries of the water cooling tube. I learned from the below "~ decade-ago" COMSOL forum thread, that I can solve this problem using "Form Assembly" instead of "Form Union"! https://www.comsol.com/forum/thread/25843/manipulating-heat-transfer-coefficient

However, using Form Assembly might create the following problems/difficulties: 1- It doesn't support the "automatic" continuity whether for meshing or physics solution at the boundaries between two adjacent domains. I.e. the user should always set some "surface Pair" BC. Because the real model is a bit complicated, I really appreciated that COMSOL takes care of such interfaces automatically (in the Form Union case)! 2- Even with using "Form Assembly", I am not able to correctly "Heat Flux 1 -->T_ext" BC to the water Temp instead of ambient!

Therefore, my questions are: 1- How can I set the heat transfer coefficient on the surface of the cooling tube in "Form Union" case? In the attched simplified model! 2- How can I set "Heat Flux 1 -->T_ext" BC to the water Temp instead of ambient, in the "Form Assembly" case? In the attched simplified model!

I have also attached a pdf file descriping the model and the case!

Best regards, Tamer



0 Replies Last Post 2020年11月18日 GMT-5 09:05
COMSOL Moderator

Hello Tamer Tolba

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.