ANSYS transient thermal boundary conditions

[cehen]

Hi all. I don't have as much experience with thermal analyses in ANSYS, and I can't quite figure out a problem that I'm working on. I'm trying to find the temperature distribution in a box that has a circle in the center. I want to define constant temperature b.c.'s at the walls and the circle has a transient heat generation rate.

My approach has been to model the box as a rectangle with a hole in the center with the conductivity, heat capacity, and density of air. I then define the circle in the center with defined conductivity, heat capacity, and density. My problem is how to define the b.c. at the interface between the circle and the box. If it was just a regular convection problem, i know how to define T-infinity and the film coefficient, but in this situation, I don't quite know how to define the heat transfer between the air in the box and the circle in the center.

Thanks!

 

[Achy47]

Hi there,

Great question! It sounds like you are on the right track with your approach of modeling the box as a rectangle with a hole in the center. In order to define the boundary condition at the interface between the circle and the box, you will need to consider the heat transfer between the air in the box and the circle in the center.

One option is to use a convective boundary condition at the interface, which would take into account the heat transfer coefficient between the two regions. This can be calculated using the Nusselt number, which is dependent on the geometry and flow conditions.

Alternatively, you could use a thermal contact resistance boundary condition at the interface, which takes into account the resistance to heat transfer between the two regions. This can be determined experimentally or through theoretical calculations.

I would recommend consulting with a thermal analysis expert or referring to ANSYS documentation for specific guidance on how to define the appropriate boundary condition for your specific case.

I hope this helps, and good luck with your analysis!