CFD Online Discussion Forums - Lagrange particles not moving

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Lagrange particles not moving

Hello all,
I modified a simplefoam solver to include temperature, porous media and lagrange particle tracking. I'm trying to solve the flow for a steady-state case in parallel, but i'm experiencing a strange problem. I'm using the flow field from an already converged case as the initial 0 field. After introducing the particles at the inlet patch they remain roughly in the same position for subsequent iterations.
Below is the kinematicCloudProperties file i'm using which was derived from the steady-state particle solver simpleReactingParcelFoam particle properties file.
I'm supsecting two issues:-
1) The particles are stuck just before the first porous zone. I implemented the porosity as a momentum sink in the UEqn not as a physical barrier and didn't think this would be an issue since the particle should take the path of least resistance.
2) I'm setting something wrong in my kinematicCloudProperties file. I've not used steady-state particle tracking before and just used the file fro simpleReactingParcelFoam with very little modification.
Anyone with any idea of what could be wrong. I'm using the openFoam v6.

Code:

/*--------------------------------*- C++ -*----------------------------------*\

| =========                 |                                                 |

| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |

|  \\    /   O peration     | Version:  4.x                                   |

|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |

|    \\/     M anipulation  |                                                 |

\*---------------------------------------------------------------------------*/

FoamFile

{

    version     2.0;

    format      ascii;

    class       dictionary;

    location    "constant";

    object      kinematicCloudProperties;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



solution

{

    active          true;

    coupled         false;

    transient       no;

    

    calcFrequency   10;  //added

    maxTrackTime    5; //added

    cellValueSourceCorrection off;

    maxCo           0.3; 



    interpolationSchemes

    {

        rho             cell;

        U               cellPoint;

        mu              cell;

        DUcDt           cell;

    }



    integrationSchemes

    {

        U               Euler;

        T               analytical;

    }



    sourceTerms

    {

        resetOnStartup  no; //added

        schemes

        {

            U           semiImplicit 1;

        }

    }

}



constantProperties

{

    rho0            1200; //was 8800

    youngsModulus   1.3e5;

    poissonsRatio   0.35;

}



subModels

{

    particleForces

    {

        sphereDrag;

        

        gravity;

        

        pressureGradient

        {

            U U;

        }



    }



    injectionModels

    {

        model1

        {

            type             patchInjection;

            massFlowRate     0.8e-04;

            parcelBasisType  mass;

            patchName        influent;

            parcelsPerSecond 1000;

            duration         1;  //set to 1 for steady state

            U0               (-60 0 0);

            flowRateProfile  constant 1;

            //nParticle        1;

            //SOI              10;



            sizeDistribution

            {

                type        fixedValue;

                fixedValueDistribution

                {

                    value   15e-6;

                }

            }

        }

    }



    dispersionModel none;



    patchInteractionModel  localInteraction; //was standardWallInteraction



    localInteractionCoeffs

    {

        patches

        (

            "effluent|soldischarge"

            {

                type escape;

            }

            ".*"

            {

                type rebound;

                e    0.97;

                mu   0.09;

            }

        );

    }



    surfaceFilmModel none;



    stochasticCollisionModel none;

    

    collisionModel none;    



    pairCollisionCoeffs

    {

        maxInteractionDistance  0.00007;



        writeReferredParticleCloud no;



        pairModel pairSpringSliderDashpot;



        pairSpringSliderDashpotCoeffs

        {

            useEquivalentSize   no;

            alpha               0.12;

            b                   1.5;

            mu                  0.52;

            cohesionEnergyDensity 0;

            collisionResolutionSteps 12;

        };

        

        wallModel wallSpringSliderDashpot;



        wallSpringSliderDashpotCoeffs

        {

            useEquivalentSize no;

            collisionResolutionSteps 12;

            youngsModulus   1e10;

            poissonsRatio   0.23;

            alpha           0.12;

            b               1.5;

            mu              0.43;

            cohesionEnergyDensity 0;

        };

    }

}



cloudFunctions

{

    particleTracks1

    {

        type            particleTracks;

        trackInterval   5;

        maxSamples      1000000;

        resetOnWrite    yes;

    }

}



// *************************************************************************

Below is the picture of the particles stuck at the porous zone.

Eventually figured out the problem. I increased the maxTrackTime to a higher value. Now the particles move past the region.

Lagrangian particles + thermal transport

Quote:

Originally Posted by obiscolly50 (Post 726586)

Hello all,
I modified a simplefoam solver to include temperature, porous media and lagrange particle tracking. I'm trying to solve the flow for a steady-state case in parallel...

Hello obiscolly,

As I've been working on similar cases, I have a quick question: how did you handle the thermal transport to particles? I am asking this because normally the "thermo" library for particles (and generally for fluids, if I am not mistaken) is associated with compressible solvers. So, isn't it incompatible with an incompressible solver like "simpleFoam" by default?

Regards

Quote:

Originally Posted by manalis (Post 733371)

I didn't consider heat transfer from/to particles for my analysis unfortunately. I believe some of the particle tracking classes already take this into consideration by using particle properties such as specific heat e.g reactingCloud. But i didn't need that for my analysis. It would probably be more compatible with a solver like chtMultiRegionFoam which can also be used for incompressible.

Quote:

Originally Posted by obiscolly50 (Post 726586)

Eventually figured out the problem. I increased the maxTrackTime to a higher value. Now the particles move past the region.

Hi obiscolly,

I'm a real beginner in OpenFoam and I'm trying to implement the lagrangian particle transport on a steady-state problem.

I followed the tutorial https://www.foamacademy.com/wp-conte...les_slides.pdf, but on a SIMPLE scheme. I followed the same steps as in the tutorial and the compilation was successful.

I am doing verification tests on the pitzdaily tutorial, but no particle is traced (kinematicCloud folder is not created after the foamToVTK command).
What I can display in paraview is just the solid fraction, and it seems that solid particles don't evolve through the domain, even if I increase the maxTrackTime value.
Which value do you suggest?

Have you ever experienced this issue? Have you found a way to overcome it?
I'm working on OpenFoam 4.x.

Thank you very much for your support.
Any suggestion will be very much appreciate. :)