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How to apply Heat Transfer Coefficient
Posted 18 nov. 2020, 09:05 UTC−5 Fluid & Heat, Heat Transfer, Modeling Tools & Definitions Version 5.4 0 Replies
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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
Hello Tamer Tolba
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