Agitation of liquid by a cylindrical mixer

Update: July 10, 2017
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/multiphase/driftFluxFoam/ras/mixerVessel2D

Summary

We calculate the mixture of water and sludge that is agitated for 10 seconds with a rotor as shown below. The volume fraction of sludge is 0.1% and water and sludge are mixed evenly. The rotor is modeled with MRF function.

Model geometry Model geometry

The region "rotor" rotates at 6.2831853 rad/s with the Z-axis as the rotation axis to agitate the water and sludge. The gravity acceleration is set to (0, -9.81, 0). The calculation is performed as a two-dimensional problem with a single mesh in the Z direction.

Therotation axis and the number of rotations are defined in the file "constant/MRFProperties" as follows.

MRF1
{
    cellZone    rotor;
    active      yes;

    // Fixed patches (by default they 'move' with the MRF zone)
    nonRotatingPatches ();

    origin    (0 0 0);
    axis      (0 0 1);
    omega     constant 6.2831853;
}

The rotation area is defined as the cell zone "rotor" as shown in the figure below (white part).

Cell zone rotor Cell zone "rotor"

The meshes are as follows, and the number of mesh is 3072.

Mesh Meshes

The calculation result is as follows.

Volume ratio of sludge at final time (alpha.sludge) Volume ratio of sludge at final time (alpha.sludge)

We can see that the sludge (alpha.sludge) has been separated and adhered to the stator and vane parts.

Commands

cp -r $FOAM_TUTORIALS/multiphase/driftFluxFoam/ras/mixerVessel2D mixerVessel2D
cd mixerVessel2D

m4 < system/blockMeshDict.m4 > system/blockMeshDict
blockMesh
topoSet
setsToZones -noFlipMap

driftFluxFoam

paraFoam

Calculation time

21.21 seconds *Single, Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz