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[GAMBIT] boundary conditions in gambit

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Old   October 26, 2012, 00:02
Default boundary conditions in gambit
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hi everybody

i'm trying to simulate a section of a gas turbine blade in fluent with cooling holes and for the geometry, mesh and boundary conditions i use gambit. The solution in fluent present a divergence, i think that some detail in the boundary conditions is wrong, i dont know if all the faces in my geometry must have a boundary condition (wall, interior, etc.) because i let some faces without boundary condition, also i dont know the difference between internal and interior bc. could u help me with these doubts please?

thanks in advance
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Old   October 26, 2012, 13:55
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if all your domain is well connected; then you don t need to define interior or internal faces.
Also all the outer surfaces you didn t define will be regrouped as wall boundary.

Now in fluent check if all the boundaries are present in the boundary panel and check if you have some shadow-wall
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Old   October 26, 2012, 14:06
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Max, thanks for your response

then i guiess that a bad connection is the reason for my problems, how could i check the coneectiviti in gambit?
i thinked that are well connected because all the domains sharing faces.

thanks again bro
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Old   October 26, 2012, 14:14
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yes you cab check the connectivity of faces here http://202.118.250.111:8080/fluent/G...m#gc_speccolor
Surfaces should appear in pink if surfaces are connected.
Another method for checking, is picking any volume and trying to MOVE it (not copy)
If you can move it; then you have connectivity problem
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Old   October 26, 2012, 14:23
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then maybe isn't connectivity because all my domains appear pinks. aditionally i tried to move all volumes and gambit dont let me. What do u think? is there another way to solve my problem?
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Old   October 26, 2012, 14:29
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any wall-shadow in fluent BC-list?
If you stop the diverging solution, you can display the solution.Then display velocity and check if you don t have "wall" which stop the fluid flowing
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Old   October 26, 2012, 16:20
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5 wall shadows.

i can't display velocity but i can display pressure and
nothing interrupt the fluid flowing
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Old   October 27, 2012, 11:56
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display and locate wall shadows in fluent; and fix connectivity in gambit
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Old   October 28, 2012, 00:28
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then the solution is fix the zones where wall shadows appear although there is heat transfer in those walls?
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Old   October 28, 2012, 02:59
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post some pictures for understanding
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Old   October 28, 2012, 17:43
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Hi Max

100000 thanks for your help

a short description, the fluid enters the channel with a temperature a pressure and the cooling enters the plenum and goes out to cool the blade , then there is heat transfer in the blade, the first picture show the geometry and type zones, the second one show the areas that Fluent wall shadows

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Old   October 28, 2012, 17:51
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another doubt

the surfaces around the cooling holes must be wall oe interior? these surfaces belong to a solid and the cooling holes are fluids

Last edited by galapago; October 28, 2012 at 19:40.
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Old   October 29, 2012, 04:06
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can you post first picture with shaded mode turned on?
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Old   October 29, 2012, 14:46
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Hi Max

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Old   October 30, 2012, 03:37
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I am not experienced with solid conduction, I recommend you: http://aerojet.engr.ucdavis.edu/flue...e567.htm#86350

Also I recommend you to simplify your physic and start without solid elements (no solid conduction).
Then when you get congerged solution, increase complexity with solid conduction
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