Heat transfer problem at fluid-solid interface
I'm learning Fluent and I'm trying to model transient heat transfer from a metal cylinder to air by natural convection. I'm having trouble with interfaces and I'm not sure on the best approach, hopefully you can help. I am using Workbench 14.5, DesignModeler, ANSYS Meshing and of course Fluent. Here is what I have done.
1. Create a cylinder(solid) in DM
2. Create a box (fluid) which is larger than, and surrounds the cylinder
3. Boolean subtract of the cylinder from the box whilst preserving the tool body (the cylinder)
4.Created 3 named selections; cylinder, env, hotface. env represents the environment which is air and hotface is one end of the cylinder which will have a heat flux applied to it.
5. I mesh this using the Workbech Meshing program using default settings, a contact region with 3 faces is detected
6. In Fluent, 3 wall boundary conditions are created; hotface, wall-cylinder and wall-env.
7. I apply gravity, incompressible-ideal-gas (as an air property) and a heatflux to hotface.
Result: there is heat transfer to the cylinder but none to the environment.
Ideas: I have changed the Zones 'wall-cylinder' and 'wall-environment' to interfaces, created a mesh interface using these and got convection happening. Fluent creates 3 walls and a single corresponding shadow wall when I do this. This seems a bit messy as when I create the mesh interface there are 3 faces for 'wall-cylinder' and 9 faces for 'wall-env' (3 from the cylinder and 6 from the box.
What is the best way to approach this problem?
Thanks in advance :)
Alright so I figured out that a much simpler way is to form all bodies into a single part in DesignModeler and then coupled walls and shadow walls are created as there is a conformal mesh. Much easier!
You could also mesh only the fluid (do not preserve booleans tool body) an use a shell conduction approach to model conduction in the cylinder.
Many thanks for your advice Markat, so much to learn and sometimes the User's guide doesn't spell out the basic things like this.
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