[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
• 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/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