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-   -   Is the mixerVessel2D tutorial from reactingMultiphaseEulerFoam actually working? (https://www.cfd-online.com/Forums/openfoam-solving/226764-mixervessel2d-tutorial-reactingmultiphaseeulerfoam-actually-working.html)

MazenDraw May 7, 2020 07:23

Is the mixerVessel2D tutorial from reactingMultiphaseEulerFoam actually working?
 
4 Attachment(s)
I tried running the mixerVessel2D tutorial from both OpenFOAM Foundation v 7 and OpenFOAM v 1912.


On OF 7 the tutorial finishes but the results look wrong (see attachments).


On OF 1912 the tutorial crashes at T = 3.8 s, and the results of the older time steps look also wrong.


Can someone confirm this to me please?

HPE May 7, 2020 12:25

It blows up for v1912, it was discovered here: https://develop.openfoam.com/Develop...e_requests/347

"
multiphase/interFoam/RAS/DTCHullMoving with hierarchical decomposition throws Floating point exception for unmodified and modified cases.

multiphase/reactingMultiphaseEulerFoam/laminar/mixerVessel2D throws error for unmodified and modified cases.

multiphase/reactingTwoPhaseEulerFoam/RAS/LBend returns different results for separate runs even though I have not modified this tutorial at all.
"

MazenDraw May 7, 2020 12:42

Quote:

Originally Posted by HPE (Post 769275)
It blows up for v1912, it was discovered here: https://develop.openfoam.com/Develop...e_requests/347

"
multiphase/interFoam/RAS/DTCHullMoving with hierarchical decomposition throws Floating point exception for unmodified and modified cases.

multiphase/reactingMultiphaseEulerFoam/laminar/mixerVessel2D throws error for unmodified and modified cases.

multiphase/reactingTwoPhaseEulerFoam/RAS/LBend returns different results for separate runs even though I have not modified this tutorial at all.
"


Do you also happen to have OF v7? Because there it is not crashing but IMO the results look wrong. Can you also confirm that?
I wanna know if there is an issue with MRF with reactingMultiphaseEulerFoam in general in those releases, because I am trying to create a case setup with MRF in reactingMultiphaseEulerFoam but it's not working. However, the same setup is working with reactingTwoPhaseEulerFoam.

HPE May 7, 2020 13:17

no idea, sorry. might consider to ask the Foundation by using one of the links below.

HPE May 8, 2020 07:16

- Could you please elaborate, if possible, why the results look wrong to you? Is there any benchmark data you do compare with?

MazenDraw May 8, 2020 07:27

Quote:

Originally Posted by HPE (Post 769424)
- Could you please elaborate, if possible, why the results look wrong to you? Is there any benchmark data you do compare with?


The pressure field should be low in the rotating region, and high in the stationary region. This pressure gradient is created in stirred tank cases and it causes the flow back to the rotating region. This is not the case here. In this tutorial, you get pressure gradient which is not related to this phenomenon. You can check the results of the mixerVessel2D of reactingTwoPhaseEulerFoam to see what I am talking about.


Also the max velocity magnitude is much higher than it should be. It is 5.6 m/s for air velocity and 1.1 m/s for water velocity. However, the inner region with r = 0.05 m is rotating with speed of 10 rad/s. Therefore, the highest magnitude should be around 0.5 m/s.


Compare the results of mixerVessel2D of rTPEF with the results of mixerVessel2D of rMEF and tell me what you think.

MazenDraw May 8, 2020 07:45

4 Attachment(s)
Quote:

Originally Posted by MazenDraw (Post 769425)
The pressure field should be low in the rotating region, and high in the stationary region. This pressure gradient is created in stirred tank cases and it causes the flow back to the rotating region. This is not the case here. In this tutorial, you get pressure gradient which is not related to this phenomenon. You can check the results of the mixerVessel2D of reactingTwoPhaseEulerFoam to see what I am talking about.
.


I checked the pressure field in rTPEF case, and it looks constant everywhere. Now I am confused!


However, the velocity vector field looks good to me.


I think you are right. I need a validation case to tell whether results are physical or not.


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