View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001395 | OpenFOAM | Bug | public | 2014-09-08 23:36 | 2015-03-06 19:34 |
| Reporter | Assigned To | henry | |||
| Priority | high | Severity | major | Reproducibility | always |
| Status | closed | Resolution | fixed | ||
| Platform | Linux | OS | Ubuntu | OS Version | 12.04 |
| Summary | 0001395: Inconsistent thermo properties liquid mixtures for lagrangian droplets | ||||
| Description | When having a liquid spray composed of two different liquids, the order of specification in thermophysical properties between the thermophysical properties of the liquids in the droplets. In the attached example, urea (CH4N2O in liquidProperties) and water droplets are being injected into air. If the case is run as is, the urea evaporates completely before the water. If the order of entries for CH4N2O and H2O are switched in thermophysicalProperties, then the water evaporates completely before the urea. I believe the correct behaviour should give the same results no matter the order. | ||||
| Steps To Reproduce | 1. Download the case ureaTest.tar.gz 2. Extract and run blockMeshDict and topoSet on the case 3. Run sprayFoam on the case (if possible, the case is formatted to run on 4 processors in parallel) 3. Note the mass fraction of urea in the liquid droplets in ParaFoam and you will see the droplets gradually contain only water before being completely gone 4. Now re-run the case with the order of entries in thermophysicalProperties reversed (water first then urea) the droplets are now completely urea before complete evaporation | ||||
| Additional Information | There is also an issue with the surface tension where some droplets will crash the simulation as both mole fractions will be less than SMALL when calculating sigma in liquidMixtureProperties.C, line 379. I modified it to have it return (sigma + SMALL) in that case. | ||||
| Tags | No tags attached. | ||||
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2014-09-08 23:36
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Could you clarify: > crash the simulation as both mole fractions will be less than SMALL when calculating sigma in liquidMixtureProperties.C, line 379. I modified it to have it return (sigma + SMALL) in that case. I assume you have added a test for XsSum > SMALL or similar but I don't understand the need for (sigma + SMALL). Also are the mole/mass fractions of all components -> 0? |
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It was just a quick workaround to get a non-zero sigma returned to prevent the simulation from crashing. The second problem may be more related to thermophysics, as all the component mole/mass fraction approach zero. There is probably a better way of dealing with this issue. |
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Do you need sigma to be non-zero? Do ALL the component mole/mass fractions approach zero? Surely if they are actually fractions they should sum to 1. |
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It appears that there are serious issues with the current handling for liquid mixtures in the Lagrangian library. Have you investigated what might be causing the dependency on the order of specification in thermophysical properties? If the mass/mole fractions are really not summing to 1 I think this needs to be fixed first. |
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With the help of Niklas Nordin we have a fix for the sigma problem which we are testing along with other improvements to liquidMixtureProperties. I am now working on the addressing inconsistency between the liquid mixture and the thermodynamics package. |
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This is now fixed in OpenFOAM-dev: commit b44d2ba049a90a62ed7e178ee88336ebf649b1d0 Author: Henry <Henry> Date: Thu Mar 5 11:35:49 2015 +0000 lagrangian: Rationalized the handling of multi-component liquids and solids Ensures consistency between the mixture thermodynamics and composition specifications for the parcels. Simpler more efficient implementation. Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1395 as well as other consistency issues not yet reported. It needs more testing after which I can back-port to OpenFOAM-2.3.x if needed. |
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Orphaned report |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2014-09-08 23:36 |
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New Issue | |
| 2014-09-08 23:36 |
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File Added: ureaTest.tar.gz | |
| 2015-02-24 17:56 | henry | Note Added: 0003894 | |
| 2015-02-24 18:01 |
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Note Added: 0003895 | |
| 2015-02-24 18:08 | henry | Note Added: 0003896 | |
| 2015-02-26 10:35 | henry | Note Added: 0003917 | |
| 2015-03-03 16:46 | henry | Note Added: 0003950 | |
| 2015-03-05 11:44 | henry | Note Added: 0003960 | |
| 2015-03-06 19:33 | henry | Note Added: 0003995 | |
| 2015-03-06 19:33 | henry | Status | new => closed |
| 2015-03-06 19:34 | henry | Assigned To | => henry |
| 2015-03-06 19:34 | henry | Resolution | open => fixed |
