[Darku]

Hi all,
I'm trying to learn fireFOAM and i've seen that you asked several questions about it so I assume you already learned it

My problem is: I tried to start tutorial smallPoolFire2D. I created mesh and type fireFoam. After some time I got this result (2 sec, temperature):



As you can see, teperature didn't change. I wanted result like this:



which is taken from presentation by FM Global - google doc

Can you please tell me where is problem?

Thank you very much.

Darku

[meenu_1]

Hellow Darku,
I had faced similar problem, but after some trial and error finally i found the solution.
Just check out the "Allrun" file in the "smallpoolfire2D" tutorial case folder. and run all the command . It should give you the temperature rise.

Happy FOAMing

[meenu_1]

run these commands
$blockMesh
$topoSet
$createPatch -overwrite
$fireFoam
even i am new to OpenFoam and i dnt know what the 2nd and 3rd command do, but it run the tutorial properly.
If anybody can explain it , that will be great help.

[jmdf]

topoSet - "operates on cellSets/faceSets/pointSets through a dictionary." It can be used to create zones inside the mesh that could be used to split the mesh into regions or assign different properties on each zone. https://openfoamwiki.net/index.php/TopoSet

createPatch - "Utility to create patches out of selected boundary faces. Faces come either from existing patches or from a faceSet." I think it says it all https://openfoamwiki.net/index.php/CreatePatch

[meenu_1]

Thanks Ferreira, for the insight. i will look into links for more details

[luca1992]

Hi , sorry, I'm trying to use the smallPoolFire3D solver to simulate a fire in the tunnel. I thought the blockMeshDict file that originated the cube was the heat puddle from which the fire came out and then I put the heat puddle cube inside the tunnel. Now I have doubts, which may sound stupid, but I'm having some problems so I'm trying out all the options, although I do not think, that I should put the tunnel inside the cube created with the blockMeshDict file because it represents the maximum domain of the problem. You can help me?

Thank you, kind regards, Luca.

[Darku]

Hi Luca,

if I understood correctly, you have some large domain and inside it there is small puddle which is on fire. As mantioned by jmdf and meenu_1, you can use topoSetDict. This allows to create new area (boundary) with different settings - see smallPoolFire3D/system/topoSetDict. With this you can create 2D "box" and in createPatchDict you name it like it is ordinary boundary. Then you set all variables in 0 folder for this new boundary.

Hope it will help.

Darku

[luca1992]

Hello Darku, thanks for the answer ,
yes, exactly, I'm trying to simulate a fire in a tunnel.Yes I added to the files in folder 0 the information on this new boundary. I created the external mesh (just the edge) with solidworks in .stl format and I put the cube representing the heat puddle inside. My question is: does the heat puddle be placed in the tunnel, or do I have to enlarge the cube of the heat puddle and put the tunnel inside the cube? I have some doubts about topoSetDict and createPatchDict. Can you help me?

[Bdew8556]

Hey Lucca,

I'm trying to do the same thing.
I don't suppose you have a template file I could use? ie nothing sensitive just a run down of the file structure, what commands you ran etc?

[ingraban]

- Start off with the smallPoolFire3D tutorial
- adapt blockMeshDict to represent the geometry of your tunnel
- define the fire source geometry in topoSetDict: cell faces inside the box are selected as group f0 (or any other name you choose).
- edit createPatchDict: the group of faces f0 is defined as a patch (here: inlet)
- define the initial and boundary conditions in the /0 folder. For a tunnel, you may have to use wall functions, flow profile on the inlet etc. I am still trying to figure out the right boundary conditions.
- edit decomposeParDict: for a tunnel, you'd want to have the division for parallelisation along the length of the tunnel and not in quarters

then run ./Allrun

This should give you a pool fire in an empty tunnel.

[luca1992]

Sorry for not having answered you immediately, now I've seen the notification and I'll answer you below, I hope it's not late.

[luca1992]

Originally Posted by Bdew8556

Hey Lucca,

I'm trying to do the same thing.
I don't suppose you have a template file I could use? ie nothing sensitive just a run down of the file structure, what commands you ran etc?

Hi Bdew8556, I'm again really sorry but I didn't receive or didn't see the notification of your question on the forum. I saw that fortunately another user answered you.

I don't know if you still need it anyway I have made many attempts and in the end I used Blender to which I added the Swiftblock extension which allowed me to create the empty geometry of the tunnel by creating a blockMeshDict file (the advantage is that I created it in a graphic way and the extension wrote me the lines of code of the file). Then I took a stl file from the internet, modified it and inserted it into the tunnel (changing the coordinates). Then snappyHexMesh removed the tunnel's cells that coincided with the geometry of the stl file.

Let me know and sorry again, bye

[manjirigr23]

is this enough to model pool fire?. I have different fire source (methanol). what all are the things i need to edit. so far i have edited in 0 folder (U velocity, Fuel name, k value) and in the constant folder (radiationproperties-hiTcoeff, reaction-single step, thermocompressiblegas-high/lowcp values for ch3oh), in system folder (based on my computational capacity).

is this itself enough or i am missing something big to model methanol pool fire, my motive is to validate temperature and velocity profile of methanol pool fire

[JiinY]

Hello,

I am currently running a `fireFoam` simulation using OpenFOAM version 7, but I am experiencing an issue where the temperature does not increase during the simulation.

Have you encountered a similar issue, and if so, were you able to solve it?

I would greatly appreciate any advice or guidance.
Thank you in advance!

Best regards,
Yejin

[manjirigr23]

Hey JiinY, Can you be more specific where you are visualizing your case? If it is in ParaView then just rescale after completeting your simulation.

[JiinY]

Hello,

Thank you for your response.

I am running the `smallPoolFire2D` tutorial simulation using the `fireFoam` solver in OpenFOAM version 7. However, I am encountering an issue where the temperature does not increase during the simulation.

In the terminal output, the solving for `rho`, `H2O`, `CH4`, and `CO2` shows:
Initial residual = 0, Final residual = 0, No iterations 0

Additionally, the temperature remains constant with:
min/max(T) = 300, 300

When I visualize the results in ParaView, the temperature stays at the initial value of **300 K** with no change throughout the simulation. Based on the terminal output, it seems that the chemical reaction and ignition are not occurring.

Could you please advise on how to resolve this issue?

Thank you in advance for your help!

[manjirigr23]

hey, it seems your simulation itself is not running. Have you edited any files in 0, constant or system folders? also check the commands you are giving to run.

[JiinY]

Thank you for your response.

I haven't modified any other folders. I followed the execution order of blockMesh, topoSet, createPatch, and fireFoam, but there is still no temperature change during the simulation. Could there be an issue with the inlet condition generated by topoSet or createPatch?

Also, in the 0 folder, both the inlet temperature and the internalField are set to uniform 300;. Could this be related to the issue?

in blockmesh file;
vertices
(-0.5, 0, -0.01)
(0.5, 0, -0.01)
(0.5, 1, -0.01)
(-0.5, 1, -0.01)
(-0.5, 0, 0.01)
(0.5, 0, 0.01)
(0.5, 1, 0.01)
(-0.5, 1, 0.01)

blocks
(
hex (0 1 2 3 4 5 6 7) (150 150 1) simpleGrading (1 1 1)
)

in toposet file;
name f0;
type faceSet;
action new;
source boxToFace;
sourceInfo
{
box (-0.0529 -0.001 -0.1)(0.0529 0.002 0.1);
}

Thank you in advance for your help.

[manjirigr23]

hi, have you checked your mesh is everything ok for mesh? I think your mesh is a problem .First try running tutorial file without editing anything in it.

[JiinY]

Thank you for your response. I checked the mesh.

I confirmed that the temperature increases when running the simulation using the Allrun command.

--------------------terminal----------------------
Running blockMesh on /home/~/smallPoolFire2D
Running topoSet on /home/~/smallPoolFire2D
Running createPatch on /home/~/smallPoolFire2D
Running fireFoam on /home/~/smallPoolFire2D

However, when I manually execute the commands (blockMesh -> topoSet -> createPatch -> fireFoam) in the same order shown in the terminal after running Allrun, the temperature does not increase, even though I did not modify any folders. Why does this happen?

I would appreciate any help if anyone has experienced a similar issue.