[James_mCFD]

I've set up my geometry using Design Modeller. I have a solid object which represents my fluid body, and I've created an external thin wall with a thickness of 0 from this object and combined these two objects as one part.

I've meshed this body, named the thin wall as a hot temperature source and named the surface of the fluid body (excluding inlet and outlet), as the cold walls. I can't select the internal sides of the thin wall as when I hide the internal body and try to select the internal sides, it just highlights the external faces.

What I want to do is utilise this thin wall as a constant temperature boundary, and run a transient simulation so the fluid flow in the internal solid object (really confusing nomenclature - that doesn't help ), is heated by this thin wall over time.

My issues are, I can't create a contact between the internals of the thin wall and the edge of the fluid body. I can also not see the thin wall in the "Boundary Conditions" table when setting up the simulation calculation.

I don't understand why there is not just an option to set the wall temperature of the fluid body to a different temperature to the interior of the fluid body at the beginning of the calculation.

I'm using Ansys 18.1, and all guidance would be much appreciated.

[Gert-Jan]

What solver do you want to use?

[James_mCFD]

I'm using a Laminar solver in fluent (microchannels being simulated, and if Mesh is fine enough it is accurate).

A quick fix that was advised to me by a colleague was to use Standard Initialisation as opposed to Hybrid Initialisation, and set the initial temperatures relative to the inlet.

[Gert-Jan]

I would suggest to use CFX which has more tools to handle thin surfaces, interfaces, etc. Might be new for you, but that is my experience.