CFD Online Discussion Forums - inject different sized particles

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inject different sized particles

Hi Foamers,

I do not have any idea about injection type, except the doc I find in the tutorials. Now I can only inject one sized particles.

Code:

        sizeDistribution

        {

            type        fixedValue;

            fixedValueDistribution

            {

                value   0.2;

            }

        }

How can I inject two sized particles, like 0.1 and 0.2 at the same time?

If its important that the size is either 0.1 or 0.2, I would use 2 injectors

Quote:

Originally Posted by niklas (Post 410353)

If its important that the size is either 0.1 or 0.2, I would use 2 injectors

Thank you for your reply.

So should I use two 'CloudProperties' files or two injection in the same 'CloudProperties' file?

does anyone have some ideas?

Hello czhao86,

I just saw this and it might be useful to you http://www.openfoam.org/version2.2.0...-modelling.php
You could specifiy two injectors of the same model having different size distributions.
Also you only need one sprayCloudProperties file.

regards,

ris.

Thank you for your reply, ris.

I am using icoUncoupledKinematicParcelFoam, whose injection is like the following

Code:

solution

{

    active          true;

    coupled         false;

    transient       yes;

    cellValueSourceCorrection off;



    interpolationSchemes

    {

        rho             cell;

        U               cellPoint;

        mu              cell;

    }



    integrationSchemes

    {

        U               Euler;

    }



    sourceTerms

    {

        schemes

        {

        // Scheme and under-relaxation factor

          U               semiImplicit 0.5;

//        U               explicit 1.0;

        }

    }



}



constantProperties

{

    parcelTypeId    1;



    rhoMin          1e-16;

    minParticleMass 1.0e-15;



    rho0            1;

    youngsModulus   6e8;

    poissonsRatio   0.35;



    constantVolume  false;

}



subModels

{

    particleForces

    {

        sphereDrag;

        gravity;

    }



    injectionModel manualInjection;



    dispersionModel none;



    patchInteractionModel standardWallInteraction;



    heatTransferModel none;



    surfaceFilmModel none;



    collisionModel pairCollision;



    radiation off;



    manualInjectionCoeffs

    {

        massTotal       0;

        parcelBasisType fixed;

        nParticle       1;

        SOI             0;

        positionsFile   "kinematicCloud0Positions";

        U0              (0 0 0);

        sizeDistribution

        {

            type        fixedValue;

            fixedValueDistribution

            {

                value   0.1;

            }

        }

    }



pairCollisionCoeffs

    {

        // Maximum possible particle diameter expected at any time

        maxInteractionDistance  0.1;



        writeReferredParticleCloud no;



        pairModel pairSpringSliderDashpot;



        pairSpringSliderDashpotCoeffs

        {

            useEquivalentSize   no;

            alpha               0.12;

            b                   1.5;

            mu                  0.52;

            cohesionEnergyDensity 0;

            collisionResolutionSteps 12;

        };



        wallModel    wallLocalSpringSliderDashpot;



        wallLocalSpringSliderDashpotCoeffs

        {

            useEquivalentSize no;

            collisionResolutionSteps 12;

            walls

            {

                youngsModulus   1e10;

                poissonsRatio   0.23;

                alpha           0.12;

                b               1.5;

                mu              0.43;

        cohesionEnergyDensity 0;

            }

        };

    }



    standardWallInteractionCoeffs

    {

        //type            stick;

        type            rebound;

    }

}





cloudFunctions

{



}

I am not sure where to add the second injection, as the format is a little different, but certainly thank you for your reply.

Quote:

Originally Posted by ris (Post 412089)

I figured out openfoam 2.2.0 has a different format of 'injectionModels' even in the tutorials, compared to 2.1.1.

I saw this webpage but did not realize its importance.

Thank you for giving me a hint.

Diifferent numbers of particle injection?

Dear Foamers,
I'm currently working with the solver iconUncoupledKinematicParcelFoam (lagrangian).
I need to inject a different number of particles at each time step.
I'm currently using the model "patchInjection" in the file kinematicCloudProperties.
The problem is, I dont know how to make the number of particels vary.
Is there a way to force the number of particles to vary by wether providing a table (for number of particles vs. time) or as a function?
Any suggestions, ideas are very welcome.
Please, my master thesis depends on this.
Regards!
Mamadou.

Normal Distribution

Quote:

Originally Posted by czhao86 (Post 412074)

does anyone have some ideas?

I think you can define the size of particles to be normal distributed. For instance:

sizeDistribution
{
type normal;
normalDistribution
{
expectation 0.0001;
variance 2.16e-10;
minValue 0.00005;
maxValue 0.00015;
}
}

Hope it helps

Zonghao