reactingFoam - species do not move

sebastian610 · May 24, 2013, 10:03

I am running a very simple pipe flow with reactingFoam. Inlet - wall - outlet. The thermochemistry setup is the same as for the reactingFoam tutorial. I see the velocity and pressure going through the pipe with time as one would expect, but not the species. My initial setting is 100% N2 in the volume and I am setting air for the b/c at the inlet. I should see O2 being convected into the pipe. Species equations are being solved and written, but the species' values remain almost unchanged. I tried to increase the initialChemicalTimeStep, to no avail.
I seem to be missing out the obvious thing. Thanks for suggestions.

sebastian610 · May 25, 2013, 06:04

I found the mistake: the mesh was written in mm instead of m.

I take the path freeCAD - gmesh - engrid - openfoam. Although the step file from freeCAD was correctly written in m, gmesh wrote the mesh out in mm which later openfoam interpreted as m.

remedy: transformPoints -scale '(0.001 0.001 0.001)'

It is always a good idea to check the points file for the correct units.

If someone knows how to set the default in gmesh permanently to meters, please answer to this post.

May 24, 2013, 10:03	reactingFoam - species do not move	#1
sebastian610 New Member Sebastian Join Date: May 2013 Posts: 7 Rep Power: 13	I am running a very simple pipe flow with reactingFoam. Inlet - wall - outlet. The thermochemistry setup is the same as for the reactingFoam tutorial. I see the velocity and pressure going through the pipe with time as one would expect, but not the species. My initial setting is 100% N2 in the volume and I am setting air for the b/c at the inlet. I should see O2 being convected into the pipe. Species equations are being solved and written, but the species' values remain almost unchanged. I tried to increase the initialChemicalTimeStep, to no avail. I seem to be missing out the obvious thing. Thanks for suggestions.

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May 25, 2013, 06:04		#2
sebastian610 New Member Sebastian Join Date: May 2013 Posts: 7 Rep Power: 13	I found the mistake: the mesh was written in mm instead of m. I take the path freeCAD - gmesh - engrid - openfoam. Although the step file from freeCAD was correctly written in m, gmesh wrote the mesh out in mm which later openfoam interpreted as m. remedy: transformPoints -scale '(0.001 0.001 0.001)' It is always a good idea to check the points file for the correct units. If someone knows how to set the default in gmesh permanently to meters, please answer to this post.