View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0003635 | OpenFOAM | Bug | public | 2021-03-03 13:50 | 2021-03-03 14:55 |
| Reporter | blttkgl | Assigned To | henry | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | no change required | ||
| Platform | GNU/Linux | OS | Ubuntu | OS Version | 15.04 |
| Product Version | dev | ||||
| Summary | 0003635: default combustionProperties option turns chemistry off | ||||
| Description | In reacting OpenFOAM solvers if the combustionProperties file is not provided in the constant folder, OpenFOAM selects a "no combustion" (none) model and runs the simulation still. I believe that this may lead to user error, because this effectively turns off the chemistry and returns zero for both Qdot and reaction rate of the chemical species. Turning the chemistry on or off is already controlled via the "chemistry" keyword in chemistryProperties. I think that if a combustionProperties file is not provided, the solver should either 1) use a no-model approach instead of no-combustion, which corresponds to the "laminar" combustion model that passes the Qdot and RR calculated in chemistryModel directly, or 2) throw a warning and complain about unspecified combustion model. | ||||
| Steps To Reproduce | run counterFlowFlame2D_GRI tutorial by deleting the combustionProperties file under constant. | ||||
| Tags | No tags attached. | ||||
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we note that this change is brought in OpenFOAM-6, and in 5 and earlier an error message was thrown when this file wasn't provided: --> FOAM FATAL ERROR: cannot find file "/u/97/tekgulb1/data/Desktop/counterFlowFlame2D_GRI/constant/combustionProperties" |
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> In reacting OpenFOAM solvers if the combustionProperties file is not provided in the constant folder, OpenFOAM selects a "no combustion" (none) model and runs the simulation still. That is correct, this is to support specie mixing without reaction which is a common request. If you want to enable reaction simple set the appropriate entries in combustionProperties. |
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I understand, but wouldn't setting the chemistry flag to "off" in chemistryProperties does the exact same thing? Why do you need that flag then if one can just set a "none" combustion model if they want no reactions? |
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The reacting solvers are not pure laminar, they support turbulence and turbulent combustion models. The chemistryProperties file does not define the combustion model, only the chemistry for combustion models that require it. If you want to run laminar combustion you will need to specify the laminar combustion model in combustionProperties and the chemistry in chemistryProperties. Alternatively you could write a specific laminar only solver which would not need a combustion model. |
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I realize reacting solvers are not pure laminar, but in combustionModel "laminar" means that it passes the Qdot and RR calculated by the chemistry model without making any changes to it. If you use a different combustionModel (PaSR, EDC), these variables are changed in the combustionModel according to the model definition and passed to the solver. If combustionModel is not specified, it is set as "none", which returns Qdot and RR = 0 to the solver. This last option is practically the same thing with setting the chemistry as "off" in chemistryPropertiesDict. I can set the chemistry to be off, then it wouldn't matter which combustion model I use (none, laminar, EDC, etc.), because it will pass 0 for Qdot and RR, which means mixing without reactions. Now if one wants to run a reacting solver without reactions they have two ways of doing either set chemistry off from chemistryProperties, or set combustionModel as none in combustionProperties, or just do not include that file at all. This is why I find this confusing. In this sense chemistry flag in chemistryProperties is redundant because if I want non-reacting simulation I can just set combustionModel to "none", right? It may seem like splitting hairs but there have been quite a confusion within our group regarding this so I wanted to open an issue for anyone who might experience this in the future. Bulut |
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I don't see a problem with creating a combustionProperties file, if you need help with this you could arrange a support contract and we can help you directly. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2021-03-03 13:50 | blttkgl | New Issue | |
| 2021-03-03 13:57 | blttkgl | Note Added: 0011902 | |
| 2021-03-03 14:09 | henry | Note Added: 0011903 | |
| 2021-03-03 14:12 | blttkgl | Note Added: 0011904 | |
| 2021-03-03 14:30 | henry | Note Added: 0011905 | |
| 2021-03-03 14:42 | blttkgl | Note Added: 0011906 | |
| 2021-03-03 14:54 | henry | Note Added: 0011907 | |
| 2021-03-03 14:55 | henry | Assigned To | => henry |
| 2021-03-03 14:55 | henry | Status | new => closed |
| 2021-03-03 14:55 | henry | Resolution | open => no change required |
