[guido_adriaensen]

Hello everybody,

I would like to simulate the following with the engineFoam solver of openFoam: I have cilinder in which two pistons move towards eachother. Is it possible to simulate this with the engineFoam, by simply adjusting the cilinderHead type to symmetry? I have not tried this, I will try this tomorrow, unless someone can already tell me that this will not work. If this will not work, could you please tell me how this would be possible to simulate in openFoam?
Thanks for your input!

Regards

Guido Adriaensen

[lucchini]

Hi Guido,

that sounds something interesting on the engine point of view!

Try to consider the cylinderHead as a symmetryPlane and then check the pressure value you get at the end of the compression stroke and the velocity field.
In this way you can understand if the assumption is good or not.
If you want to do something a bit "better" and simulate the full geometry you should have to modify the movePiston.H file to allow the motion of both the pistons.
To do that you have to study the following files:
$FOAM_SRC/engine/include/movePiston.H
$FOAM_SRC/engine/include/createEngineMovingMesh.H
$FOAM_SRC/engine/engineTime/engineTime.H
$FOAM_SRC/engine/engineTime/engineTime.C
and then modify a bit the movePiston.H and createEngineMovingMesh.H files

have fun!
tommaso

[guido_adriaensen]

Hi Tommaso,

Thanx for your reply!
I will modify the kivatest case and try to run it today with the cylinderhead specified as symmetryPlane. I will keep you informed on the progress.
This will be just the start however, I want to simulate the full geometry and thus will have to adjust those files you mentioned.

Regards
Guido Adriaensen

[guido_adriaensen]

Hello!

I've simulated the compression stroke with the cylinderhead defined as symmetryPlane. Everything seemes to be going fine :-).
Currently I'm working on the second approach, the simulation of the full geometry. I've studied the movePiston.H, createEngineMovingMesh.H and engineTime.C / engineTime.H files. Currently I'm editing these files in order to simulate the two moving pistons. If I have some results for that as well or run in to trouble (hopefully the first :-) ) I will report it here.

[guido_adriaensen]

Hello,

Is the TF9307 report available on the net? Or could somebody email it to me? I would appreciate it very much.

I have been working on the simulation of the full geometry, for which I have adjusted the movePiston.H and createEngineMovingMesh.H and engineTime.C (and .H) files. But when I try to run my case I get an error that the patch of cylinderHead is not found. The error refers to /home/dm2/henry/.../createEngineMovingMesh.H.
I have altered the createEngineMovingMesh.H file( I have commented the part where it should raise the fatal error when no cylinderHead-patch is found), but it seems like it does not use my altered file. For the 2 moving pistons there is no cylinderHead, that why it is not found of course.
I'm using version 1.1 of OpenFOAM.

Regards

Guido Adriaensen

[lucchini]

Hi Guido,
I have the TF9307, so you can write me and I can send it to you.
Concerning the error you got, did you recompile the engineFoam application before running it?
Bye
Tommaso

[guido_adriaensen]

Hi,

Thank you very much Tommaso for the report!
Since I'm using openFOAM 1.1, I cannot use the boundary condition for wallFixedTemp and movingWallFixedTemp, but I would like to use these boundary conditions. As mentioned in http://www.cfd-online.com/OpenFOAM_D...ages/1/37.html there is an error in the heat transfer, which relates to the wrong temperature. This would be corrected in the thermodynamics package of version 1.1.1. Does anybody have the correct files that I could use, or tell me which ones I have to adjust in order for engineFoam to be able to run with these boundary conditions. Or should I upgrade to version 1.2? Thanks for the info!

Guido