[czhao86]

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.

        sizeDistribution
        {
            type        fixedValue;
            fixedValueDistribution
            {
                value   0.2;
            }
        }

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

[niklas]

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

[czhao86]

Originally Posted by niklas

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?

[czhao86]

does anyone have some ideas?

[ris]

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.

[czhao86]

Thank you for your reply, ris.

I am using icoUncoupledKinematicParcelFoam, whose injection is like the following

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.

[czhao86]

Originally Posted by ris

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.

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.

[camzis]

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.

[Dust]

Originally Posted by czhao86

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