[Mechand]

Hello everyone,

I was going through the Fluent documentation and this forum but I couldn't find out a solution to my problem.

I wanted to model a heat exchanger where one fluid transports heat to the other fluid where both are separated by a solid region. I created a mesh and everything. Eventuallly, I have mesh interfaces where I selected coupled for the fluid and solid zones, respectively. I also got a solution, but one thing that worries me is that in wall boundary conditions I have like:

contact_region_10_wall1-1-1(wall, id=229)
contact_region_10_wall1-1-1-shadow(wall, id=232)
wall_1_fluid-contact-region_10-src-non-overlapping(wall, id=230)
wall_1_solid-contact-region_10-trg-non-overlapping(wall, id=231)
And those last two walls were created after I set coupled in mesh interfaces.

I am not sure if I should have so many walls that seem to refer to one thing
Moreover, In the first two walls, I have coupled option marked.
But in the last two, I still can choose wall boundary conditions. I also tried setting different values of heat transfer coef, or free stream temp., but it turned out it did not affect the solution.

Any advice would be helpful

[MKuhn]

The last two walls are not coupled together. You have to check your geometry, that these is only one face or use the mapped option in fluent to couple these non-overlapping walls.