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no183 October 28, 2010 09:57

meshing and boundary condition
As the picture show, the computer casing is mesh on the component (motherboard, HDD, etc) but this is not i want as i want to know the heat flow profile that inside the casing, which is the area not been mesh, so how do i done that?
and what is the boundary condition i can set?

-mAx- October 29, 2010 01:03

you are meshing the outer surfaces of components, which is correct since they are surface limits of your domain
Just check if you can select components as volume. If yes, then you need to delete them, as far as you don't want to compute any solid conduction.

no183 October 29, 2010 05:52

can, but it select the whole casing, i cant choose anything..

-mAx- October 29, 2010 05:58

so you only have one volume, and components surfaces are part of the volume, right?
It means your components are empty and only their outer surfaces will be meshed.
So that is correct.
You try to compute heat transfer in the domain defined between the casing and components (boolean substract between whole casing and components results in what you actually have)

no183 January 5, 2011 03:32

sorry, away from online since holiday..
Now, i still cant get what u mean, is it anyone here can assist me on that? give me a step by step tutorial

no183 January 5, 2011 03:35

btw, any tutorial for fluent and gambit?

-mAx- January 5, 2011 04:26

provide me your .dbs file

no183 January 5, 2011 07:45

how? email?

no183 January 5, 2011 07:47

i save it in stp file

-mAx- January 5, 2011 08:24

send the dbs file (save your session in Gambit).
In this way I can observe errors you can have.
Upload the file on a share server like rapidshare or whatever

no183 January 5, 2011 10:00
here it is..
kindly state what u have done, i mean how u done it, as i am still a learner. thanks

-mAx- January 6, 2011 02:20

1 Attachment(s)
As I thought, you only have solid elements.
Since you want to compute heat exchange, you don't need solid elements, but the air volume contained in your model.
If you enable shaded mode (render icone) you will see that your box isn't close at the top (cf picture)
So I would create a surrounding volume (englobing all your solid elements) and substract this closed box with all your solid elements.
Create a surface by sweeping edge 2112 with vector (0 -440 0)
Create a volume by sweeping created face with vector (0 0 -190.5)
That will be your surrounding volume.
Finally substract all your solid elements from this volume. The result will 2 volumes, with one small you need to delete
If you look at the bottom (shaded mode on) you will see that you don't have the solid elements anymore, but only their outter surfaces.
Tha'ts what you need.
Attachment 5981

no183 January 6, 2011 09:09

bro, i manage to do the first 2 step.. but the third step how? frankly, i am idiot in FLUENT, as this model i drawn from solidwork, this is my first time using FLUENT, forgive my weakness.

-mAx- January 6, 2011 09:38

1 Attachment(s)
right-click on the icon (actually the unite icon is displayed)
Attachment 5987

no183 January 6, 2011 09:44

ya, i get that, but which subtract to which.

-mAx- January 6, 2011 09:50

*biggest volume as first entry
a*ll other (solid parts) as second entry (understand you can select multiple volumes)

no183 January 6, 2011 09:56

hmm, what is the biggest volume btw, there are few volume that can be selected at the casing..

-mAx- January 6, 2011 10:00

the biggest volume, is the one you just created (the one generated with your 2 succesfully steps)
In other words: none of your imported (solid) parts

no183 January 6, 2011 10:03

so is the last volume created, in other word, the largest number?

-mAx- January 6, 2011 10:11

independantly from your volume id, select the volume surrounding the others.
It will be red displayed. If it is not the volume you want, click on the middle clik of your mouse, it will select another, etc...
Once you selected the right one, check its name in the pick-box
Else you open the journal file or the transcript file (or navigate in the transcript window) and check the id given to the volume after the sweep face operation.

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