boundary conditions in gambit
 

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

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

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

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

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?

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

5 wall shadows.

i can't display velocity but i can display pressure and
nothing interrupt the fluid flowing

display and locate wall shadows in fluent; and fix connectivity in gambit

then the solution is fix the zones where wall shadows appear although there is heat transfer in those walls?

post some pictures for understanding

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 shadowshttp://i268.photobucket.com/albums/j.../cfdonline.png

http://i268.photobucket.com/albums/j...ner/shadow.png

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

can you post first picture with shaded mode turned on?

Hi Max

http://i268.photobucket.com/albums/j...ner/shaded.png

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

hi
I am also working on this turbine blade cooling can you please tell me how the boundary conditions were taken.Can we give coolant mass flow inlet? for each cooling channel.