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-   -   why droplet is not formed in micro channel (https://www.cfd-online.com/Forums/openfoam-solving/136137-why-droplet-not-formed-micro-channel.html)

taajaki May 23, 2014 01:02
why droplet is not formed in micro channel
 
1 Attachment(s)
Hi Foamers.
I am trying to simulate a micro channel and I expect to see droplets in it but as you can see here the droplets are not formed . Blue color is oil(continuous phase) in main channel and the red one is water (dispersed phase) which is flow in two lateral channels.(I have two lateral channel and one main channel).
Is there any comment ?
thanks for your attention
these are boundary conditions :
alpha.water
Code:
boundaryField
{
  oil
    {
        type            fixedValue;
        value                uniform 0.0;
    }
    water-1
    {
        type            fixedValue;
        value                uniform 1.0;
    }
    water-2
    {
        type            fixedValue;
        value                uniform 1.0;
    }
  outlet
    {
        type            zeroGradient;
    }

    walls
    {
        type            zeroGradient;
    }
 

    defaultFaces
    {
        type            empty;
    }


}
alpha.water.org
Code:
internalField  uniform 0;

boundaryField
{
  oil
    {
        type            fixedValue;
        value                uniform 0.0;
    }
    water-1
    {
        type            fixedValue;
        value                uniform 1.0;
    }
    water-2
    {
        type            fixedValue;
        value                uniform 1.0;
    }
    outlet
    {
        type            zeroGradient;
    }

    walls
    {
        type            zeroGradient;
    }
 

    defaultFaces
    {
        type            empty;
    }


}
p_rgh
Code:
internalField  uniform 0;

boundaryField
{
    oil
    {
        type            zeroGradient;
    }
    water-1
    {
        type            zeroGradient;
    }
    water-2
    {
        type            zeroGradient;
    }
    outlet
    {
        type            fixedValue;
        value                uniform 0;
    }

    walls
    {
        type            zeroGradient;
    }

 
}
U
Code:
boundaryField
{
  oil
    {
        type            fixedValue;
        value          uniform (0.01386 0 0);

    }
   
    water-1
    {
        type            fixedValue;
        value          uniform (0 -0.011 0);
    }
    water-2
    {
        type            fixedValue;
        value          uniform (0 -0.011 0);
    }

    outlet
    {
        type                zeroGradient;
    }

    walls
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }

}

taajaki May 26, 2014 15:22
contact angel in micro channel two phased flow
 
hi everyone
this is my third question in succession that none of them were answered :confused:however I hope to find the solution and post it here to help others...
I have a micro channel which you can see it here
I have a question about defining contact angel in this micro channel hopefully to see droplets in main channel.
1-Is it necessary to define contact angle to making droplets?(boundaries are correct?)
2-Is it suppose to define in main or lateral channels?
3-In which phase should I define it and how?
thank you

wyldckat August 16, 2014 07:05
Greetings taajaki,

Sorry for the late reply, but I only now managed to have a somewhat better look at your questions.

For what I can figure out so far, the VOF approach in OpenFOAM does not yet contemplate micro-fluid behaviour or at least not very well. Here are some threads I've kept some track on regarding this issue, perhaps you can figure out something more from them:
Best regards,
Bruno

taajaki October 23, 2014 02:21
thanks for your attention Bruno
could you please take a look at this question: http://www.cfd-online.com/Forums/ope...o-channel.html

thanks alot


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