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-   -   Meshing in CHT Problem (http://www.cfd-online.com/Forums/fluent/111505-meshing-cht-problem.html)

Markat January 8, 2013 16:24

Meshing in CHT Problem
 
I try to mesh my geometry (thin plate). The minimum orthogonal quality is about 0.1 and the average about 0.9. The residuals are about 1e-05 after 1000 iterations and can not be further reduced.
Some elements have negative value of wall heat transfer, which I cannot physically explain.
1. Is it important to use inflation or should I ignore inflation to achieve a better minum orthogonal quality?
2.Should I try to use Polyherdal meshing to improve minimum orthogonal quality? Can Polyherdal meshing be used for CHT problems? When I used Polyhedral meshing the maximum value of wall heat transfer was being almost doubled in comparison with Tetrameshing. How could you explain this?

Thank you in advance

Markat January 10, 2013 16:56

Could anybody please help me?

Markat January 13, 2013 13:36

Does anybody have any idea?

diamondx January 13, 2013 13:59

post screenshot of you mesh !! and your geometry !! is it 2d or 3d ?? what software did you use to mesh ??

Markat January 13, 2013 14:45

Thnak you for yyour reply! My mesh is 3d and was made in Ansys Mesher (Workbench)

diamondx January 13, 2013 14:57

can i see how it looks like

Markat January 13, 2013 16:14

I unfortunately don't have an availiable picture of my meshing right now, but I will post one as soon as possible! Thank you in advance for your help

Markat January 13, 2013 16:16

Just to imagine it looks like an thin airfoil in a wind tunnel. Only a the fluid was being meshed (I used boolean subtraction to create the appropriate geometry).

diamondx January 13, 2013 16:38

it should be easy to mesh with a structured mesh under ICEM are you familiar with icem. when the geometry is easy; always go for a structured mesh if you can.

Markat January 13, 2013 16:45

Thank you for your advice! I tried to do a structured mesh! Unfotunately the mesh in the area near the airfoil (cambered) can not be structured.
When I try smoothing the meshing in Fluent I got a better minimum orthogonal quality (~0.4). The simulation result remained unchanged (energy residuals do not ger below 10^-5 so I thought I should try to solve my problem transient)!


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