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Simulating Air Convection between Active and Inactive Heating Elements
Posted 29 mars 2021, 23:09 UTC−4 Electromagnetics, Electromagnetic Heating, MEMS & Nanotechnology Version 5.5 1 Reply
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I have been constructing a model that is made up of an array of heating elements. So far using the Joule Heating multiphysics in COMSOL, I am able to simulate the heat conduction of my active wires through their casings and the block of which the entire array rests upon. However, this model is incomplete, as despite accounting for the heat flux through the outer boundaries to ambient air, the heat flux boundary condition does not account for the heat flow that convects in the open space between the heaters. I have explored the extents of the boundary condition options and believe that I might need to put the model inside a large block of 'air', but am lost beyond that.
My goal is to model the thermal crosstalk between heating elements, ideally where one is active, and the adjacent ones are inactive. There is heat conduction through the base they are all connected to but without the heat convection across the spaces between them, this is only a partial model. These heaters/wires are on the order of um, and the spaces between them ~100um.
If anyone has any insight, it would be most appreciated.
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Hello Nicholas,
You are talking about conjugate heat transfer (i.e. heat transfer in both solids and fluids, see this blog post on that topic ) with the source of the heat being electric.
One model of this nature with detailed instructions is the busbar example found in the Introduction to COMSOL Multiphysics manual, version 5.6. You can access that manual from within the COMSOL software by going to File > Help > Documentation. Most manuals are not on our website, but this one is; you will find it here. The busbar tutorial starts on page 62, and the fluid domain is added starting on page 131.
Your own model may be a bit more complex, since you may need to include radiative effects that are ignored in the busbar example, but that tutorial should at least help you get started.
Best regards,
Jeff
-------------------Jeff Hiller