## General Mechanical

#### Surface body into fluent 3D simulation

• jlekuona
Subscriber

I am simulating the thermal behaviour of a battery cell while it's being cooled with a cold plate from one side. Heat is generated in the solid inside the cell, which is in contact with the large sides of the case only. The heat is conducted through the case to the cold plate. As I only consider conduction from the inner body to the case, there is no material in the empty volume inside the cell. I have added a picture of the problem and the inner parts of the cell.

The cell case is made of a thin aluminium sheet. If I model the case as a solid body everything works fine, but its mesh requires a lot of elements. Thus, I am trying to model it as a shell element with only 2D. The idea is to add a thicknes to the wall (in thermal boundary conditions) and allow for shell conduction in thin walls.

The problem is that when the mesh is translated into fluent, the case in 2D is ignored and only the mesh of the solid bodies is displayed.

Is there a workaround for this?

Is it just that 2D surface bodies cannot be translated into fluent in 3D mode?

• Rob
Ansys Employee

We can't have surfaces without cells in the CFD codes.  However, if you model the outer case as a thin wall with shell conduction you'll get much the same effect as having a solid case. It's explained in the User's Guide under wall (thermal) conditions.

• jlekuona
Subscriber

Thank you for your reply rwoolhow, as you suggested my intention is to use shell conduction.

When I try to model the outer case as a thin wall, I generate a surface mesh for it. My problem is that this surface mesh is not imported into fluent. How can I generate a mesh for a thin wall that is not ignored by fluent?

• Rob
Ansys Employee

You need to import the solid/fluid volumes: Fluent doesn't recognise surface mesh in 3d.  The enclosure case will be the surface of the enclosure volume (where the fluid is).