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-   -   How to solve 2 diferrent specify continuum types (http://www.cfd-online.com/Forums/fluent/42592-how-solve-2-diferrent-specify-continuum-types.html)

tuw October 17, 2006 09:37

How to solve 2 diferrent specify continuum types
 
Hi all,

Any suggestion is much appreciated!

Basically, I am modelling a solid model (with heat generation) and also the surrounding air around it. My purpose is to see:

1. the thermal distribution of the solid,

2. the temperature of the fluid and also

3. the fluid flow pattern (if i assign a certain velocity inlet to the fluid).

Therefore i would have 2 continuum zone which is specified during my session in gambit 2.2.30.

2Zones:

1. my solid - solid

2. surrounding air - fluid

For the wall boundary between the 2 zones, i use "face --> connect face" to combine the 2 faces into 1 for each coupling faces. For example, a face from the solid is combine with another similar face from the fluid. The face is then defined as internal boundary.

However, when i proceed to Fluent 6.2.16, the error as below appear:

__________________________________________________ _________

Warning: materials in neighbor cell threads (2 and 3) of

interior zone 4 are of different types (aluminum and air).

This problem MUST be fixed before solving!

Warning: materials in neighbor cell threads (2 and 3) of

interior zone 4 are of different types (aluminum and air).

This problem MUST be fixed before solving!

__________________________________________________ _________

I am stucked. Please help me! Thousand thanks for spending your time in helping my problem and replying!

Tuw

University of Malaya

Malaysia

tuwtzekhai8@yahoo.com

Razvan October 20, 2006 04:03

Re: How to solve 2 diferrent specify continuum typ
 
From your message, the only mistake evident to me was that you forced definition of the face separating fluid and solid zones to INTERNAL. You don't have to assign no boundary conditions to this face, Fluent solver will handle it. All you have to do is to make sure that it is ONE face only (I mean connected). If there are TWO faces, with same (or different) grid, geometrically identic, then after reading the grid in Fluent, you will have to define these two faces as INTERFACE (Fluent will automatically assign WALL boundary condition to them when reading the grid), and then define an interface in "Define/Interface..." GUI menu. Don't forget to check the "Coupled" option too (it tells Fluent that this is a fluid-solid interface). Be careful on heat transfer settings for the solid walls too...

All the best, Razvan

tuw October 28, 2006 11:30

Re: How to solve 2 diferrent specify continuum typ
 
Dear Razvan,

Many thanks for your help! It seems that i can model 2 different types of continuum now... After several attempts, i found that the iteration turn out well and smoothly where the residual gradually decrease at first. However, after 20+ iteration, the energy equation's residual keep increase exponentially.

My way of setting the heat transfer is by specifying the heat generation (W/m3) of the solid continuum (not the wall's heat generation). I also set the outer fluid continuum as constant temperature wall boundary condition. Despite of that, i also use pressure inlet and pressure outlet on 2 surfaces (applying pressure inlet on 1 surface and pressure outlet to another surface) of the outer fluid continuum.

Can i ask for your advice in setting the heat transfer setting, like you mention earlier? Thanks! =]

Tuw


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