# twoPhaseEulerFoam (very) high pressure when using kinetic theory

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 May 13, 2016, 04:58 twoPhaseEulerFoam (very) high pressure when using kinetic theory #1 Senior Member     Ruben Di Battista Join Date: May 2013 Location: Paris Posts: 137 Rep Power: 12 Hello everybody, I'm basically simulating a slurry flow with solid particles in a liquid carrier. I managed to run simulation with different turbulent models for the liquid carrier (basically k-w SST and std. k-epsilon) getting reasonable velocity profiles and pressure drops. In most of the papers I'm trying to emulate (i.e. CFD modeling for pipeline flow of fine particles at high concentration - Kaushal et al.) they use kinetic-theory for granular flow. I tried to enable it but I get a practically laminar profile for the solid phase. Here an image that compares the two velocity profiles with same volume fraction (13%), inlet velocity (1.5), particle diameter (1.3mm), k-w for carrier and in the red profile I used the kinetic-theory for granular flows with equilibrium hypothesis. GEOMETRY DETAILS Pipe Diameter: 15e-3 [m] Pipe Length: 0.6 [m] Gravity: [0 0 -9.81] Position of the sample line: 0.4 [m] from the inlet Boundary Conditions: inlet:U.carrier: 1.5 [m/s] U.dispersed: 1.5 [m/s] k: Intensity 0.005 U.carrier (turbulentIntensityKineticEnergyInlet) omega.carrier: FixedValue 1 alpha.carrier = FixedValue 0.13 p = calculated p_rgh = zeroGradient Theta.dispersed = FixedValue 0 nut for both: calculated outlet:U.carrier: zeroGradient U.dispersed: zeroGradient k: zeroGradient omega.carrier: FixedValue 1 alpha.carrier = FixedValue 0.13 p = calculated p_rgh = zeroGradient Theta.dispersed = FixedValue 0 nut for both: calculated wallsU.* = no-slip k = LowReWallFunction/Std Wall Function (depends from the mesh) omega = Wall Function p = calculated p_rgh = zeroGradient Theta = zeroGradient nut: calculated symmetryPlane:symmetry for all PHASES INFORMATIONS Liquid Carrier Density: 870 [Kg/m³] Liquid Carrier Viscosity: 0.292E-3 [Pa s] Dispersed Phase Density: 1026 [Kg/m³] Dispersed Phase Viscosity: 0.292E-3 [Pa s] (Case naming system: 15_13_kw_keq: 15 = 1.5 m/s inlet velocity 13 = 1.3mm particle diameter kw = k-omega sst turbulence for carrier keq = kinetic theory with equilibrium ) Seems to be related to viscosity provided by the model: it's basically a laminar profile so I would say that there is not enough viscosity. An help would be very appreciated, thanks... OpenFOAM 3.0.1 Here is my case too: cfd-online.tar.gz HPE likes this. Last edited by rdbisme; May 20, 2016 at 05:53.

 April 13, 2020, 12:00 #2 New Member   Masoud Kahnooji Join Date: Sep 2017 Location: Iran Posts: 5 Rep Power: 8 Hello Ruben (tidusuper91) I am simulating slurry flow by twophaseeulerfoam, and I study your case. I am surprised because of your refine mesh (very small). I read that "The cell size is chosen to be roughly about 30 times the particle diameter of the solid phase, and If a finer mesh should be used, it is important that the size of the control volumes is not smaller than the diameter of the particle. In a control volume smaller than the particle diameter, the particle would fill the entire control volume (αp = 1) and not allow for e.g., particle-particle interactions.", but the minimum volume size of your mesh is smaller than particle volume. What is your idea about the size of the mesh when we use twophaseeulerfoam for slurry flow? I know that your question was in 2016, but could you tell me how did your problem solve? Sincerely yours

 April 13, 2020, 13:16 #3 Senior Member     Ruben Di Battista Join Date: May 2013 Location: Paris Posts: 137 Rep Power: 12 Hello Masoud, it was indeed long time ago. Where did you read that? Can you provide a reference? masoudbme90 likes this.

 April 13, 2020, 13:41 #4 New Member   Masoud Kahnooji Join Date: Sep 2017 Location: Iran Posts: 5 Rep Power: 8 Hello Ruben Thank you for your kind response . I read a tutorial about twophaseeulerfoam at Chalmers university was written by Busch: https://www.google.com/url?sa=t&rct=...j7gVliLiYwiVsf

 April 13, 2020, 16:18 #5 Senior Member     Herpes Free Engineer Join Date: Sep 2019 Location: The Home Under The Ground with the Lost Boys Posts: 932 Rep Power: 12 It has been a while that I haven't read a well prepared question such as this one in this forum. Thanks. __________________ The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror

April 13, 2020, 16:48
#6
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Ruben Di Battista
Join Date: May 2013
Location: Paris
Posts: 137
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Quote:
 Originally Posted by masoudbme90 Hello Ruben Thank you for your kind response . I read a tutorial about twophaseeulerfoam at Chalmers university was written by Busch: https://www.google.com/url?sa=t&rct=...j7gVliLiYwiVsf
Well, as I said, it was long time ago. But I don't think there's a limitation on that ratio numerically speaking. The question would then be if the results are physically sound. I was able, at the end, to extract useful profiles from this configuration.

This question was related to my M.Sc. thesis that you can find here. I hope that would help you!

April 13, 2020, 16:54
#7
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Ruben Di Battista
Join Date: May 2013
Location: Paris
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Quote:
 Originally Posted by HPE It has been a while that I haven't read a well prepared question such as this one in this forum. Thanks.
Ahahah, thanks. It was long time ago and... yet nobody answered.

 April 15, 2020, 13:38 #8 New Member   Masoud Kahnooji Join Date: Sep 2017 Location: Iran Posts: 5 Rep Power: 8 Hello Ruben Thank you for your response.

July 3, 2020, 04:52
#9
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kimy
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Hi Masoud, did you simulate slurry flow without problem? I am also doing this research.

Quote:
 Originally Posted by masoudbme90 Hello Ruben Thank you for your response.

July 3, 2020, 04:54
#10
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kimy
Join Date: Mar 2019
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Thanks for your post. I found in Fvsolution file, you used under relaxation factor. However, during the simulation, it was neglected no matter how you changed the coefficient. Also, the issue of time step is significant.

Quote:
 Originally Posted by rdbisme Hello everybody, I'm basically simulating a slurry flow with solid particles in a liquid carrier. I managed to run simulation with different turbulent models for the liquid carrier (basically k-w SST and std. k-epsilon) getting reasonable velocity profiles and pressure drops. In most of the papers I'm trying to emulate (i.e. CFD modeling for pipeline flow of fine particles at high concentration - Kaushal et al.) they use kinetic-theory for granular flow. I tried to enable it but I get a practically laminar profile for the solid phase. Here an image that compares the two velocity profiles with same volume fraction (13%), inlet velocity (1.5), particle diameter (1.3mm), k-w for carrier and in the red profile I used the kinetic-theory for granular flows with equilibrium hypothesis. GEOMETRY DETAILS Pipe Diameter: 15e-3 [m] Pipe Length: 0.6 [m] Gravity: [0 0 -9.81] Position of the sample line: 0.4 [m] from the inlet Boundary Conditions: inlet:U.carrier: 1.5 [m/s] U.dispersed: 1.5 [m/s] k: Intensity 0.005 U.carrier (turbulentIntensityKineticEnergyInlet) omega.carrier: FixedValue 1 alpha.carrier = FixedValue 0.13 p = calculated p_rgh = zeroGradient Theta.dispersed = FixedValue 0 nut for both: calculated outlet:U.carrier: zeroGradient U.dispersed: zeroGradient k: zeroGradient omega.carrier: FixedValue 1 alpha.carrier = FixedValue 0.13 p = calculated p_rgh = zeroGradient Theta.dispersed = FixedValue 0 nut for both: calculated wallsU.* = no-slip k = LowReWallFunction/Std Wall Function (depends from the mesh) omega = Wall Function p = calculated p_rgh = zeroGradient Theta = zeroGradient nut: calculated symmetryPlane:symmetry for all PHASES INFORMATIONS Liquid Carrier Density: 870 [Kg/m³] Liquid Carrier Viscosity: 0.292E-3 [Pa s] Dispersed Phase Density: 1026 [Kg/m³] Dispersed Phase Viscosity: 0.292E-3 [Pa s] (Case naming system: 15_13_kw_keq: 15 = 1.5 m/s inlet velocity 13 = 1.3mm particle diameter kw = k-omega sst turbulence for carrier keq = kinetic theory with equilibrium ) Seems to be related to viscosity provided by the model: it's basically a laminar profile so I would say that there is not enough viscosity. An help would be very appreciated, thanks... OpenFOAM 3.0.1 Here is my case too: Attachment 47417