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twoPhaseEulerFoam (very) high pressure when using kinetic theory

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Old   May 13, 2016, 03:58
Thumbs up twoPhaseEulerFoam (very) high pressure when using kinetic theory
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Ruben Di Battista
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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
  • walls
    • U.* = 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/m]
Liquid Carrier Viscosity: 0.292E-3 [Pa s]
Dispersed Phase Density: 1026 [Kg/m]
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


Last edited by tidusuper91; May 20, 2016 at 04:53.
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