[Wesley]

What is the correct way to setup a powerLaw viscosity model when using the incompressibleMultiphaseVoF solver?


I am using OpenFOAM 12.


I have not found a multiphase tutorial with a non-Newtonian fluid, so do not have a template to build from. I do have the powerLaw model working with the incompressibleFluid and the incompressibleVoF solvers.

I built the file structure assuming it should be analogous to the file structure for the incompressibleVoF solver, which I do have running and reading the powerLaw fluid model.

I believe the issue is in the “constant” directory because the only issue appears to be that I am not correctly defining the rheological model (powerLaw). The simulation is currently using only the viscosities defined in the two physical properties files.


My current file structure for the constant directory is (boundary, faces, neighbour, owner, and points are subdirectories in polyMesh, but I can't get the tree to display correctly:

├── g
├── momentumTransport
├── momentumTransport.ExtrudateA
├── momentumTransport.ExtrudateB
├── phaseProperties
├── physicalProperties.ExtrudateA
├── physicalProperties.ExtrudateB
└── polyMesh
├── boundary
├── faces
├── neighbour
├── owner
└── points

Relevant contents of the momentumTransport file:

FoamFile
{
format ascii;
class dictionary;
location "constant";
object momentumTransport;
}


simulationType laminar;

Relevant contents of the momentumTransport.ExtrudateA file (momentumTransport.ExtrudateB is similar):

FoamFile
{
format ascii;
class dictionary;
location "constant";
object momentumTransport.ExtrudateA;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //


simulationType laminar;


laminar
{
model generalisedNewtonian;


viscosityModel powerLaw;


nuMax 1000000;
nuMin 0.1;
k 3000;
n 0.4;
}

Relevant contents of the physicalProperties.ExtrudateA file (physicalProperties.ExtrudateB is similar):

FoamFile
{
format ascii;
class dictionary;
location "constant";
object physicalProperties.ExtrudateA;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //


viscosityModel constant;
nu 1.64e-3;
rho 1250;

The simulation is currently set up with 2 phases to allow me to compare to an existing 2 phase simulation using incompressibleVoF solver, but future iterations will use more than 2 phases.

Guidance/help on getting the powerLaw rheological model working with the incompressibleMultiphaseVoF solver is greatly appreciated.

[Wesley]

Until I can work out or told how to setup multiphase non-Newtonian models in OpenFOAM 12, I will use OpenFOAM 9, which uses the previous file structure.

For OpenFOAM 9, I have a directory structure of:

├── 0
│   ├── alpha.ExtrudateA 
│   ├── alpha.ExtrudateB 
│   ├── alpha.ExtrudateC 
│   ├── alphas 
│   ├── p_rgh 
│   └── U 
├── CoEx3FlowPipe.unv 
├── constant
│   ├── g 

│   ├── momentumTransport 
│   ├── polyMesh
│   │   ├── boundary 
│   │   ├── faces 
│   │   ├── neighbour 
│   │   ├── owner 
│   │   └── points 
│   └── transportProperties 
├── system
│   ├── controlDict 
│   ├── fvSchemes 
│   └── fvSolution 

The rheological models are in the transportProperties file:

FoamFile
{
    format      ascii;
    class       dictionary;
    location    "constant";
    object      transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

phases
(
ExtrudateA
{
transportModel  powerLaw;

powerLawCoeffs
    {
    k             k [0 2 -1 0 0 0 0] 3000;
    n             n [0 0 0 0 0 0 0] 0.4;
    nuMin         nuMin [0 2 -1 0 0 0 0] .1;
    nuMax         nuMax [0 2 -1 0 0 0 0] 1000000;
    }
    rho             1250;
}

ExtrudateB
{
transportModel  powerLaw;

powerLawCoeffs
    {
    k             k [0 2 -1 0 0 0 0] 300;
    n             n [0 0 0 0 0 0 0] 0.4;
    nuMin         nuMin [0 2 -1 0 0 0 0] .1;
    nuMax         nuMax [0 2 -1 0 0 0 0] 1000000;
    }
    rho             1250;
}

ExtrudateC
{
transportModel  powerLaw;

powerLawCoeffs
    {
    k             k [0 2 -1 0 0 0 0] 300;
    n             n [0 0 0 0 0 0 0] 0.4;
    nuMin         nuMin [0 2 -1 0 0 0 0] .1;
    nuMax         nuMax [0 2 -1 0 0 0 0] 1000000;
    }
    rho             1250;
}

);

sigmas
(
    (ExtrudateA ExtrudateB) 0.07
    (ExtrudateA ExtrudateC) 0.07
    (ExtrudateB ExtrudateC) 0.07
);
// ************************************************************************* //

Any help/tutorials/guidance on implementing this type of multiphase flow of non-Newtonain fluids in OpenFOAM 12 would be greatly appreciated.

Wes