Cavitation around a propeller

Update: July 1, 2017
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/multiphase/interPhaseChangeDyMFoam/propeller

Summary

We calculate the cavitation (bubbles that form and disappear due to pressure differences) that occurs around a propeller for 0.1 second. The propeller rotates on its axis in the mainstream direction in a tube.

Model Model

The fluid flows in from the region "inlet" at (0, -15, 0) m/s and out from the region "outlet". The propeller rotates on the Y-axis with a time-dependent rotation speed of 628 rad/s at first and then 419 rad/s. The rotation area, axis, and speed are specified in the file "constant/dynamicMeshDict" as follows.

dynamicFvMesh   solidBodyMotionFvMesh;
motionSolverLibs ( "libfvMotionSolvers.so" );
solidBodyMotionFvMeshCoeffs
{
    cellZone        innerCylinderSmall;
    solidBodyMotionFunction  rotatingMotion;
    rotatingMotionCoeffs
    {
        origin      (0 0 0);
        axis        (0 1 0);
        omega       table
        (
            (0    0)
            (0.01  628)
            (0.022  628)
            (0.03  419)
            (100   419)
        );
    }
}

The meshes are as follows, and the number of mesh is 903254.

Meshes Meshes (entire)
Meshes (on YZ-plane) Meshes (on YZ-plane)
Meshes (around AMI) Meshes (around AMI)
Meshes (propeller) Meshes (propeller)

The calculation result is as follows.

Flow velocity at final time (U) Flow velocity at final time (U)
Pressure at final time (p_rgh) Pressure at final time (p_rgh)
Volume ratio of the liquid on blade surfaces at 0.03 sec Volume ratio of the liquid on blade surfaces at 0.03 sec
Volume ratio of the liquid on blade surfaces at 0.1 sec Volume ratio of the liquid on blade surfaces at 0.1 sec

We can see that the position of cavitation changes as the rotation speed changed.

Commands

cp -r $FOAM_TUTORIALS/multiphase/interPhaseChangeDyMFoam/propeller propeller
cd propeller

blockMesh
surfaceFeatureExtract
snappyHexMesh -overwrite
renumberMesh -overwrite
rm -rf 0

topoSet -dict system/createInletOutletSets.topoSetDict
createPatch -overwrite

cp -rf 0.orig 0

decomposePar
mpirun -np 4 interPhaseChangeDyMFoam -parallel
reconstructPar

paraFoam

Calculation time

  • Making meshes: 6 minutes 11.86 seconds *Single
  • Calculating: 21 hours 32 minutes 09.8 seconds *4 parallel

※Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz