Let's talk about detailed thermal modeling of Printed Circuit Boards (PCBs)! PCBs usually have multi-layers with dielectric material and layered copper traces. Typically trace layers are non-uniform. There are also thermal vias that distribute heat through the package. Therefore a locally varying thermal conductivity is required to predict the thermal field accurately. Ansys Icepak does this by importing traces (from ECAD) and creating a thermal conductivity map. Resolving each individual layer is impractical in a system-level model. In Icepak, the trace layout is used to compute varying orthotropic conductivity for the board.
The video below demonstrates how to import traces into Icepak. Then, two thermal models are considered with conduction only for the PCB and convection for the full system.
The same model will be used to determine the Joule/trace heating capability in Ansys Icepak as demonstrated in the video below: