How to use the gas combustion module ?

[Fabien852]

Hello,

I wish to use the gas combustion module but so far without success.
I tried to activate it as described in the practical user's guide but with only the basics in Fortran I can not follow the correct procedure.

Can you direct me, please, to use this module ?

I use the version 2.0.2

Thanks

[Yvan Fournier]

Hello,
How far did you get (edited usppmo.f90, compiled it, ... ?)
Best regards,
Yvan

[Fabien852]

Hello,

I took a simple case :
I wish to see a flame at one end of a tube.

I created my study folder with the GUI:
DATA
RESU
SCRIPTS
SRC

In SRC I edited the file usppmo.f90 :
I edited the line "ippmod (icoebu)" at 0, which activates the module :
- Eddy-Break Up pre-mixed flame
- Reference model Spalding

I think I need to edit the files :
usclim.f90
usebuc.f90
usini1.f90

But I don't know what to change.

Best regards,
Fabien

[Yvan Fournier]

Hello,

With version 2.0.x, the boundary conditions for gas combustion are set in usd3pc.f90, not usclim.f90 (things will be more consistent starting with 2.2).

Also, As another thread on this forum already shows (for version 2.1), I do not believe the gas combustion module works with the GUI, so you should add the "--nogui" option to "code_saturne create" (this will leave less things commented in usini1.f90).

Otherwise, the files contain quite detailed examples (probably too many rather than not enough), so you should just adapt the examples to your case. Boundary conditions contain face selection strings, sou you may also want to read the part relative to "selection" in the user documentation.

To test that your Fortran subroutines compile (i.e. syntax is correct), run "code_saturne compile -t" in the SRC directory.

Best regards,

Yvan

[Fabien852]

Thanks for the answer.

With what you said, I'll try to make a case as simple as possible to understand the functioning of the whole thing.

I tell you the steps I made :
- For the model, i took the pipe from the tutorial caelinux.
( link : http://www.youtube.com/watch?v=2caHYngt ... e=youtu.be)
I assigned :
> An inlet for air
> An inlet for gas
> The outlet
- In the terminal, I typed "code_saturne create - nogui" in my study folder, named "Combustion". It made ​​me a folder called "CAS1".
- I copied the files usd3pc.f90, usini1.f90 and usppmo.f90 in SRC folder.
- In file usd3pc.f90, I saw the boundary conditions:
> Fuel flow inlet
> Air flow inlet
> Wall
> Exit (I don't understand what it is?)
> Symmetric
I assigned the boundary conditions on faces dedicated, leaving the default settings:
> Fuel Inlet flow "CALL GETFBR ('Inletgas' NLELT, LSTELT)"
> Air flow inlet : "CALL GETFBR ('Inletair' NLELT, LSTELT)"
> Wall : "CALL GETFBR ('Wall', NLELT, LSTELT)"
I removed the lines for the boundary conditions "Exit" and "Symmetric".
- I left the settings in default in usini1.f90.
- I activated le module "diffusion flame" with the file usppmo.f90,
ippmod (icod3p) = 0
- I tested if subroutines compile well, with "code_saturne compile -t" in the folder SRC. I have no warning nor error.

That's what I did for now,
Now, I suppose that I must edit the file "runcase", isn't it ?

Fabien

[Yvan Fournier]

Hello,

No, you should not need to edit the runcase.

I may have (or probably have) missed some detail, but at first glance, what you did so far seems correct.

To see why it does not work, if your data is not confidential, posting your case setup (tar.gz file with both case and mesh, the smaller the better) would help (I could try to reproduce the error and either tell you you error or file/fix a bug).

Best regards,

Yvan

[Fabien852]

Hello,

You are really nice !
Thank you !

I attached my file.

Fabien

[Yvan Fournier]

Hello,

I may not have time to check this before next week, but I'll take a look as soon as I can.

Best regards,

Yvan

[Fabien852]

Hello,

I understand.
If it can save your time: you can just send me the files of a simple case which works, and afterwards I will analyse it, that will help me a lot.

Fabien

[Yvan Fournier]

Hello,

I just looked at your case, and found 2 errors :

- first, in DATA, the dp_FCP file must match the combustion model, so you should copy THCH/dp_C3P (and not THCH/dp_FCP) to dp_FCP (which still needs to be named dp_FCP in DATA ; sorry for that lack of logic, but things will be more consistent in future versions)

- once this is done, things are better, but fail due to missing boundary conditions. You should replace the code you removed for the "exit" condition and use that for your faces of the "Outlet" group, and things will probably go better (I did not test)

Best regards,

Yvan