Learning Forum

[ljcish26]

I want to perform a transient heat transfer analysis in Fluent by modeling an IGBT die and solder layer in 3D, but using only a 2D model for the IGBT die.
How can I apply the thickness when modeling the IGBT die as a plane, and is it possible to simulate heat transfer into the solder layer?

[Rob]

I'm not quite sure what you're asking, but have a look at the thin wall options, and "shell conduction" under Boundary Conditions. 

[ljcish26]

When modeling an IGBT die in 3D, it is represented with width, length, and thickness. However, in a 2D analysis, only the plane is modeled and the thickness is not inherently considered. What boundary conditions should be applied in Fluent to account for the thickness so that the 2D model can represent the same behavior as the 3D model?

 

 

[Rob]

It depends on what you're trying to replicate. If you're looking at heat transfer from the heat source (chip) to the base then a thin wall can be used, and then air space (fluid) and chip (solid). But as a chip is typically small compared to the size of the heat sink & casing is a 2d model as useful? 

Maybe rephrase the question a little? My experience with modelling electronics tends to be getting heat away from the hot black bits or keeping water out of the electrically active bits. 

[ljcish26]

The reason I want to start with a 2D model is that I plan to begin with a simplified problem for training an AI model and then later expand to 3D.

In this case, heat is generated in the chip and transferred through the solder layer, and I want to obtain the junction temperature of the IGBT chip over time.
So, if I model the chip as a cross-section in 2D, would it be sufficient to specify the wall thickness in the boundary conditions?

[Rob]

Which cross section? I've seen whole boards modelled as a wall surface in 3d, with the chip, heatsink & fluid all being volumes. I've also seen 2d models as a slice across the chip, so the board was a "line" in the overall model. 

Have a look at the wall boundary options, shell conduction and heat generation are the parts to focus on.