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-   -   How to assign thermal conductivity at interface between fluid and porous region (https://www.cfd-online.com/Forums/cfx/217988-how-assign-thermal-conductivity-interface-between-fluid-porous-region.html)

Goenitz June 3, 2019 09:44

How to assign thermal conductivity at interface between fluid and porous region
 
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I have thermal conductivity of material (metal foam=porous), inlet condition and wall condition. How can I assign that thermal conductivity of porous region at interface of porous-fluid region for heat transfer. (green region is interface:Fluid left, Porous right). I have neither temperature at interface, nor heat transfer coefficient nor heat flux.

Opaque June 3, 2019 12:50

Confused.

You have materials on both sides of the interface, and their thermal conductivities specified for them, correct?

Why would you need another thermal conductivity at the interface?

Goenitz June 4, 2019 15:17

Yes, I have Aluminium on one side and air on the other. They both take default thermal conductivity value. In literature, I have nothing but thermal conductivity of Al foam (porous). So as a boundary condition, I need to define thermal conductivity of interface, if possible. CFX, as shown in pic, takes either solid interface value as either adiabatic or heat transfer coefficient or as flux. So I posted the question to see if that possible. If not how to overcome this.

Goenitz June 5, 2019 08:29

Anyway, there is no option in CFX for fluid-porous interface. There is for Solid-Porous interface. At that interface just to go the GGI interface and enable "Additional Model" for the heat transfer. Here you will be asked to provide some information to formulate the resistance.

As interface is thin region, so I can assume it to be adiabatic.

ghorrocks June 5, 2019 19:23

You don't need interfaces between a fluid region and a porous region. The porous region is just subdomains inside a fluid domain. It is one domain, so no interfaces are required.

Goenitz June 6, 2019 12:20

Quote:

Originally Posted by ghorrocks (Post 735557)
You don't need interfaces between a fluid region and a porous region. The porous region is just subdomains inside a fluid domain. It is one domain, so no interfaces are required.

Actually in Sub-Domian we can assign sources in CFX. However, for every domain we have to create separate blocks and then assign it respective domain e.g.solid, porous, fluid etc.

Another Q is which I made a thread before how to assign a normal boundary condition to wall in CFX?

ghorrocks June 6, 2019 18:35

You can also define a subdomain to have a porous loss function in the source terms.

So make the porous regions subdomains and then you don't have any interfaces to worry about.


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