Learning Forum

[ss_stardust]

Hi,

I am trying to simulate a counter flow double pipe heat exchanger filled with porous media using Ansys Fluent (see pic attached). The wall between inner and annulus pipe is required to be modelled. I have created solid zones for LTNE. The boundary conditions at both sides (inner and annulus) wall are attached as pic too. For the two fluids entering at uniform temperatures at their respective inlets, the thermal condition at wall is neither constant temperature not constant flux. So, I want to ask how to give suitable boundary conditions to simulate the heat transfer.

boundary conditions.PNG

[Karthik Remella]

Hello Could you please embed your screenshots directly into the post, rather than attaching them? Ansys employees are unable to download these attachments.
Karthik

[ss_stardust]

Thanks for replying.

[Karthik Remella]

Hello Shouldn't they just be a pair of Coupled walls? Have you performed the share topology operation on your geometry?
Karthik

[ss_stardust]

The LTNE model generates solid zone overlapping the fluid porous zone. This can be done only when mesh has been loaded in FLUENT. In my model, since the wall between inner and annulus pipe has fluid on both sides, it does couple them by creating shadow wall. However, LTNE also creates a solid zone adjacent to walls on both sides which should have the same temperature as that of the walls on either side. Since the wall temperatures on either side of walls is not known in prior as it itself has the coupled boundary condition, I am unable to give boundary condition to solid LTNE zone created adjacent to the wall. So, I want to know how to couple this porous solid-wall interface.

[Karthik Remella]

Hello You can try and create an interface between the face zones you are referencing. This way, you can artificially couple these face zones. Have you tried this?
Karthik

[ss_stardust]

Thanks for replying.
Can u please explain the how to process of artificially coupling .
Also, when solution in initialized, the console shows that a connection has been established between solid and fluid porous zone. I want to ask what type of connection of conditions are being applied by Fluent solver as it is nowhere mentioned in manual.