[nash]

hi, im new here and also in using OpenFoam. I did find good explainations of using mrf in simplefoam within this forum

I am now working on the simulation of radial fan with complex geometry including casing for the fan.

Im using snappyHexMesh for the meshing and STL file for rotor, casing and MRF Domain are being used here.

the MRF Zone are defined within the sHM and the rotors walls are inside the MRFDomain. The rotor walls and also the fluid within the MRF rotate and therefore im using simpleFoam with MRF

*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    class       polyBoundaryMesh;
    location    "constant/polyMesh";
    object      boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

21
(
    frontAndBack
    {
        type            patch;
        nFaces          0;
        startFace       23495251;
    }
    inlet
    {
        type            patch;
        nFaces          0;
        startFace       23495251;
    }
    outlet
    {
        type            patch;
        nFaces          0;
        startFace       23495251;
    }
    lowerWall
    {
        type            wall;
        nFaces          0;
        startFace       23495251;
    }
    upperWall
    {
        type            patch;
        nFaces          0;
        startFace       23495251;
    }
    fan_rotor-mrf-02-layersides
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          9195;
        startFace       23495251;
    }
    fan_rotor-mrf-02
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          194950;
        startFace       23504446;
    }
   fan_casing-03
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          13678;
        startFace       23699396;
    }
   fan_rotor-mrf-layer-02
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          55326;
        startFace       23713074;
    }
    fan_rotor-mrf-01
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          219653;
        startFace       23768400;
    }
    fan_casing
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          120780;
        startFace       23988053;
    }
   fan_plane
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          182812;
        startFace       24108833;
    }
   fan_inlet
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          140059;
        startFace       24291645;
    }
    fan_outlet
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          7870;
        startFace       24431704;
    }
    fan_canal
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          123670;
        startFace       24439574;
    }
    fan_cassing-outter
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          0;
        startFace       24563244;
    }
   fan_casing-mrf
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          16511;
        startFace       24563244;
    }
    fan_casing-02
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          46960;
        startFace       24579755;
    }
    fan_rotor-mrf-layer-01
    {
        type            wall;
        inGroups        1(luefter);
        nFaces          621030;
        startFace       24626715;
    }
    mrfDomain_frameBorder-interior
    {
        type            wall;
        nFaces          0;
        startFace       25247745;
    }
    mrfDomain_frameBorder-interior_slave
    {
        type            wall;
        nFaces          0;
        startFace       25247745;
    }
)

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.7.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



dimensions      [0 1 -1 0 0 0 0];

internalField   uniform ( 0 0 0);

boundaryField
{

    frontAndBack
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }

    inlet
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }

    outlet
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }

    lowerWall
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }

    upperWall
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }

    "mrfDomain_.*"
    {
    type            zeroGradient;
    value           uniform (0 0 0);
    }

    "fan_rotor.*"
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    "fan_casing.*"
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    "fan_plane.*"
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    "fan_outlet.*"
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }
    "fan_inlet.*"
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }
    "fan_canal.*"
    {
        type            fixedValue;
        value           uniform (0 0 0 );
    }

}

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.7.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{

    frontAndBack
    {
        type            zeroGradient;
        value           uniform 0;
    }

    inlet
    {
        type            zeroGradient;
        value           uniform 0;
    }

    outlet
    {
        type            zeroGradient;
        value           uniform 0;
    }

    lowerWall
    {
        type            zeroGradient;
        value           uniform 0;
    }

    upperWall
    {
        type            zeroGradient;
        value           uniform 0;
    }

    "fan_rotor.*"
    {
        type            zeroGradient;
        value           uniform 0.;
    }
    "mrfDomain_.*"
    {
        type            zeroGradient;
    value           uniform 0;
    }

    "fan_gehaeuse.*"
    {
        type            zeroGradient;
        value           uniform 0.;
    }

    "fan_ebene.*"
    {
        type            zeroGradient;
        value           uniform 0. ;
    }
    "fan_outlet.*"
    {
        type            totalPressure;
    rho none;
    psi none;
    phi phi;
    gamma 0;
    p0 uniform 0;
        value           uniform 0.0;
    }
    "fan_inlet.*"
    {
        type            totalPressure;
    rho none;
    psi none;
    phi phi;
    gamma 0;
    p0 uniform 0;
        value           uniform 0.;
    }
    "fan_canal.*"
    {
        type            zeroGradient;
        value           uniform  0.;
    }

}

unfortunately the simulation result seems to differ from the one using Fluent.
the velocity is twice as the velocity from the Fluent-Simulation and the pressure as well.

are there any improvements so that a good result can be generated?
using other solver etc. btw are the configurations of initial conditions okay?

thank you in advance

geometry of the fan is more likely in this fluent tutorial
https://docs.google.com/viewer?url=h...df&chrome=true

[nash]

sorry to bother everyone here..
the problem resolved..

the problem is the dimension of the STL file for my cylinder MRFZone in mm.
since sHM always read in meter, so i need to use command surfaceConvert to my STL

Originally Posted by josp

Or you can scale the stl files with surfaceConvert when you clean them

surfaceConvert in.stl out.stl -clean -scale 0.001

and run sHM again using the new STL generated from surfaceConvert and everything went fine.

check your STL file before running sHM either using surfaceCheck or view STL using Paraview.

thanks josp for your solution

[arslantuf]

Hello
Can I see your fvOption or MRFZones files? Which version are you using?
I have also results off from Fluent simulations

Thank you