Straight flow channel with porous media area

Update: June 1, 2017
This tutorial cannot be run on Ubuntu 14.04 LTS version of OpenFOAM, you need to use Ubuntu 16.04 LTS version of OpenFOAM or build foamyHexMesh by yourself.
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/incompressible/porousSimpleFoam/straightDuctImplicit

Summary

We calculate a flow with a porous media that models a filter in the middle of the flow path. The fluid flows in from the region "inlet" (X minimum plane) at a volumetric flow rate of 0.1 m3/s, passes through the filter (red part), and flows out from the region "outlet" (X maximum plane).

Model geometry Model geometry

Porous media depends on the Darcy-Forchheimer law S_i = -\biggl(\mu D_{ij}+ \frac{1}{2}\rho\left \vert u \right \vert F\biggr) u_i, and for a flow velocity ui (i=x, y, z) in direction i, a generation term Si (pressure drop) in the opposite direction of flow is added to the Navier-Stokes equations. Here, μ is the viscosity coefficient and ρ is the density.

The parameters that determine the properties of the porous media, Dij, F, the direction of the properties, and the region in which the porous media, are specified in the file constant/porosityProperties as follows.

porosity1
{
    type            DarcyForchheimer;
    active          yes;
    cellZone        porosity;

    DarcyForchheimerCoeffs
    {
        d   (5e7 -1000 -1000);
        f   (0 0 0);

        coordinateSystem
        {
            type    cartesian;
            origin  (0 0 0);
            coordinateRotation
            {
                type    axesRotation;
                e1      (1 0 0);
                e2      (0 0 1);
            }
        }
    }
}

The standard k-ε model is used for the turbulence model.

The meshes are as follows, and the number of mesh is 16016. We use foamyHexMesh to create the mesh.

Mesh Meshes

If you want to visualize turbulent energy and turbulent dissipation rate, check "k" and "epsilon" in the "Properties" tab in ParaView.

Check k and epsilon in Properties tab Check "k" and "epsilon" in "Properties" tab

The calculation result is as follows.

Flow velocity (U) Flow velocity (U)
Pressure (p) Pressure (p)
Turbulent energy (k) Turbulent energy (k)
Turbulent dissipation rate (epsilon) Turbulent dissipation rate (epsilon)

We can see that the flow velocity and pressure are greatly reduced in the porous media part.

Commands

cp -r $FOAM_TUTORIALS/incompressible/porousSimpleFoam/straightDuctImplicit straightDuctImplicit
cd straightDuctImplicit

# Make meshes
surfaceFeatureExtract
foamyHexMesh
collapseEdges -collapseFaceSet indirectPatchFaces -latestTime -overwrite
collapseEdges -collapseFaces -latestTime -overwrite
checkMesh -allTopology -allGeometry -latestTime

# Update the meshes and delete the working file
latestTime=`foamListTimes -latestTime`
rm -rf constant/polyMesh
mv "${latestTime}"/polyMesh constant
rm -r [1-9]*

porousSimpleFoam

paraFoam

Calculation time

  • Making meshes: 92.2 seconds
  • Calculating: 4.8 seconds

*Single, Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz

Reference