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Old   January 20, 2014, 01:53
Default InterPhaseChangeFoam_Help
  #1
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Baris (Heewa)
Join Date: Jan 2013
Location: Japan
Posts: 86
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Dear Foam Users,

I am trying to simulate cavitation phenomena inside of nozzle and using interphasechangefoam. As you know that there are 3 transport models (Merkle, Kunz and Sauer) I have tried all of these 3 models with kwSST turbulence model however i have problems with the obtaining of cavitation region as follows;

1. If i set the initial cond. according to Velocity as follows:
==> 0/U
Code:
internalField   uniform (0 3.104 0);
boundaryField
{
    inlet
    {
        type            fixedValue;
        value           $internalField;
    }
      outlet
    {
        type            pressureInletOutletVelocity;
        phi             phi;
        value           $internalField;
    }
    wall
    {
        type            fixedValue;
        value            uniform (0 0 0);
    }
==>0/P
Code:
internalField   uniform 1e5;
boundaryField
{
   inlet
    {
         type           zeroGradient;
    }
    outlet
    {
        type            fixedValue;
         value           $internalField;
    }
    wall
    {
        type           zeroGradient;
    }
}
cavitation starts to form until to some level, however after that it disappears although flow rate is increasing. I didnt understand why this happens? (as seen in the attached fig.)

2.if i set the initial cond. according to pressure as follows:
==>0/P
Code:
internalField   uniform 1e5;
boundaryField
{
    inlet
     {
        type            fixedValue;
        value           uniform 2.8e5;
    }
    outlet
    {
        type            fixedValue;
         value           $internalField;
    }
   wall
    {
        type           zeroGradient;
    }
==>0/U
Code:
internalField   uniform (0 0 0);
boundaryField
{
    inlet
    {
        type            zeroGradient;
        value           uniform (0 0 0);
    }
    outlet
     {
        type            inletOutlet;
        inletValue       uniform (0 0 0);
    value         uniform (0 0 0);
    }
    wall
    {
        type            fixedValue;
        value            uniform (0 0 0);
    }
in this case no cavitation form obtained. Therefore i am confused. Could someone advice me something or give some insight what kind of reasons can result in these results? I increased mesh number, changed mass transport model( means i tried 3 of models) still gives same results...

In addition; For interphasechange solver (or more generally if we try simulation multiphase with mass transition which initial condition setting is more logical; pressure or velocity based?

Thanks in advance...
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Old   January 20, 2014, 01:55
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  #2
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Baris (Heewa)
Join Date: Jan 2013
Location: Japan
Posts: 86
Rep Power: 3
shipman is on a distinguished road
Sorry I forgat to say that initial velocity and pressure values are taken from the experiment...
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