[k.kshitij]

Hi All,

I'm simulating the breakup of droplet inside a cylindrical nozzle. For this purpose I wanted to calculated the frequency of the droplet diameter distribution.

For calculating this the domain is divided in to 'n' number of sections with each section having a fixed width. Each section is analysed for the droplet which is assumed to be spherical. Now each droplet diameter is calculated from droplet volume obtained by taking into account the volume fraction occupying the computational meshes and also taking the mesh size into account. To move forward with this method I wanted to know the location of a particular cell. Is there any tool by which I can know the centroid of the cell and the volume fraction present in it.

Thanks,

Kshitij

[Elham]

Originally Posted by k.kshitij

Hi All,

I'm simulating the breakup of droplet inside a cylindrical nozzle. For this purpose I wanted to calculated the frequency of the droplet diameter distribution.

For calculating this the domain is divided in to 'n' number of sections with each section having a fixed width. Each section is analysed for the droplet which is assumed to be spherical. Now each droplet diameter is calculated from droplet volume obtained by taking into account the volume fraction occupying the computational meshes and also taking the mesh size into account. To move forward with this method I wanted to know the location of a particular cell. Is there any tool by which I can know the centroid of the cell and the volume fraction present in it.

Thanks,

Kshitij

OK. After a long time, I have a similar question. How can I calculate the droplet diameter though the droplet is evaporating? I have tested calculating the volume of the droplet in controlDict with alpha.water<0.5. But since the droplet is diffusing in the air flow just give me bigger droplets. That's because alpha.water = 0.5 is not a good representative for the droplet. I also tested alpha.water=0.98 which turns infinitive values in many times, because the droplet is smearing. Although I can see the droplet in paraView but I cannot have a good statistic for the diameter.

[Elham]

Originally Posted by Elham

OK. After a long time, I have a similar question. How can I calculate the droplet diameter though the droplet is evaporating? I have tested calculating the volume of the droplet in controlDict with alpha.water<0.5. But since the droplet is diffusing in the air flow just give me bigger droplets. That's because alpha.water = 0.5 is not a good representative for the droplet. I also tested alpha.water=0.98 which turns infinitive values in many times, because the droplet is smearing. Although I can see the droplet in paraView but I cannot have a good statistic for the diameter.

Finally, I could fix it with the following steps:

1. Create a field in createFields.H :

    volScalarField evapRate
     (
        IOobject
        (
           "evapRate", 
            runTime.timeName(),
            mesh,
            IOobject::NO_READ,
            IOobject::AUTO_WRITE
        ),
        mesh,
    dimensionedScalar("evapRate", dimDensity*dimLength/dimTime, 0.0)
      );

2. Give a value in the main C file:

                  mixtureI->correct();
tmp<volScalarField>  mDotU = mixtureI->mDotU();
            evapRate = mDotU;