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twoPhaseEulerFoam - settings for water droplets in gas |
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October 25, 2012, 04:45 |
twoPhaseEulerFoam - settings for water droplets in gas
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#1 |
New Member
Michal
Join Date: Apr 2012
Location: Czech Republic
Posts: 27
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Hi,
I'd like to ask, how can i set the coefficients of Cvm, Cl, Ct? The case is the flow of water droplets in gas. Thanks. Regards, Michal |
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October 28, 2012, 21:12 |
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#2 | |
Senior Member
Dongyue Li
Join Date: Jun 2012
Location: Beijing, China
Posts: 838
Rep Power: 17 |
Quote:
I have simulate the case u said with interFoam successfully. but I cant simulate a rising bubble with interFoam. U could try that solver. its simpler than twophaseeulerfoam. |
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October 29, 2012, 01:56 |
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#3 | |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
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Quote:
For what concerns the values of the coefficients, cvm and cl are pretty much standard (see bubble column tutorial). Ct depends on your flow, and it is important only if turbulence is used. Best,
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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October 29, 2012, 05:57 |
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#4 | |
New Member
Michal
Join Date: Apr 2012
Location: Czech Republic
Posts: 27
Rep Power: 14 |
Hi,
thanks for answers. Quote:
If I use Cvm 0, Cl 0, Ct 0, the water cumulates somewhere in the domain, but the behavior of the flow is close to "correct". With the "bubble case coeffs", the conservation of the mass is OK, but the behavior of the flow is not correct. Maybe I've wrong setup of the phases. The concentration of water (alpha) is about 1e-5.
Is there something wrong? Regards, Michal |
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October 29, 2012, 10:34 |
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#5 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
The setup seems correct (droplets are phase a). What coefficient is causing the problem, Cvm or Ct (or both)?
AP
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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October 30, 2012, 04:17 |
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#6 |
New Member
Michal
Join Date: Apr 2012
Location: Czech Republic
Posts: 27
Rep Power: 14 |
Well, the problem is the Ct coefficient. (I haven't seen any changes with the Cvm 0.5.) I've tried the values 0.0 - 3.0. The "best result" with Ct = 0.2. But the solution is not OK. Mass conservation with 1% discrepancy. The distribution of water phase is strange.
Now, I'm calculating the case in laminar setup (before k-epsilon). I need more physics in twophaseEulerFoam (TEF) - surface tension and wall adhesion (both implemented in multiphaseEulerFoam - MEF). It is possible to follow MEF with implementation surface tension although the momentum equation in MEF is in conservative form (vs. phase intesive form in TEF)? If you would answer, maybe here, for others. http://www.cfd-online.com/Forums/ope...eulerfoam.html Regards, Michal |
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October 30, 2012, 21:49 |
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#7 |
New Member
T.B
Join Date: Oct 2012
Location: Norway
Posts: 8
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Hi, I am also doing a water droplet simulation in OF, and I am interested in knowing how you defined the droplets into your mesh? I cant figure out the alpha file at the moment
cheers |
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October 31, 2012, 01:41 |
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#8 | |
New Member
Michal
Join Date: Apr 2012
Location: Czech Republic
Posts: 27
Rep Power: 14 |
Hi,
Quote:
M |
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October 31, 2012, 04:27 |
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#9 |
New Member
T.B
Join Date: Oct 2012
Location: Norway
Posts: 8
Rep Power: 13 |
Sorry for stealing your thread, do you mean just by applying uniform alpha distribution at the inlet for an example?
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November 1, 2012, 03:15 |
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#10 |
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Michal
Join Date: Apr 2012
Location: Czech Republic
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August 19, 2013, 08:46 |
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#11 |
New Member
Benedikt
Join Date: Apr 2012
Posts: 7
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Hi majkl and others,
I am working on a similar project. I want to simulate a flow of air with waterdroplets (alphaair=0.99998; v(inlet)=50; T=370) into a thin air-filled volume. I solve it with compressibleTwoPhaseEulerFoam. I started with the settings of bubbleColumn and tried different settings, but I am not satisfied with the result. It looks a bit like the volume is empty at the beginning. When streaming into the volume, the inflow doesn't react with the air in the volume. The air in the volume looks like it gets replaced of the inflow, rather than getting suppressed. Did you find any information about the settings of the transportProperties? Or maybe other hints which settings could cause my unphysical behaviour? Thanks in advance Benedikt |
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