Conjugate Heat Transfer in Shell bodies
 

Hello, I am doing a structural optimization of a supersonic fighter jet wing for my end of degree thesis. To do so, I need to consider the effect of aerodynamic heating to assess thermal stresses in the wing.

Since the final objective is the sizing of the wing's structural components, I do not know the thickness of the skin beforehand, so I need to set up an iterative process to optimize this.

This is where my issues in Fluent arise. I want to study the conjugate heat transfer problem between the hot air in the boundary layer and the wing. As the wing's skin is very thin (and student's version node limits) I really don't want to mesh it, since for every value of the thickness I would need to remesh. So, I am using surfaces as shell bodies to enable shell conduction and avoid meshing the wing.

From my research on Youtube and forums, it looks like CHT problems require a solid cell zone and a fluid cell zone. This creates a shadow wall pair and enables to choose the "Coupled" wall thermal boundary condition.

I'll explain my current set-up for better understanding. I have the fluid volume I want to study, and the surface of the wing. I have performed boolean operation to substract the wing from the air volume. Then, I shared the topology such that the wing and air have a conformal mesh.

I am aware that for CFD one does not need to mesh the wing surface, but instead can apply a boundary condition to the walls of the air volume. However, I did this in an attempt to see if meshing the wing's surface would make a solid cell zone appear, which it has not.

So, the final question is: How can I set up the conjugate heat transfer problem between a fluid and a shell body? How can I create a solid cell zone such that it allows the coupled boundary condition?

What if: I mesh a solid version of the wing, which I hope it creates a solid cell zone. Then, the shadow walls appear, which I can apply the coupled BC to, and enable shell conduction throughout the wall.

Then, I would only be interested in the results of the shell. How could I retrieve them? Would the solid wing wall affect the results?

Thank you very much.

So, I think you need to subtract the wing so as to get the flow domain, but the wing solid domain must still exist. Then the two body together (flow and wing) will have a interface where the CHT problem is solved. If you delete the solid with subtract, it will not work