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How to get rid of PRefValue

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Old   June 30, 2022, 08:42
Default How to get rid of PRefValue
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Hello foamers.

I try to simulate the thermodynamic phenomena that take place in a closed enclosure heated by the walls using the multiphase solver interCondensatingEvaporatingFoam.

The problem is in 2 dimensions. It is a rectangle in which initially liquid water is contained. The 4 sides of this rectangle are walls.

boundary
Code:
(
    FrontandBack
    {
        type            empty;
        inGroups        1(empty);
        nFaces          30134;
        startFace       29826;
    }
    Left
    {
        type            wall;
        inGroups        1(wall);
        nFaces          247;
        startFace       59960;
    }
    Right
    {
        type            wall;
        inGroups        1(wall);
        nFaces          247;
        startFace       60207;
    }
    Bottom
    {
        type            wall;
        inGroups        1(wall);
        nFaces          61;
        startFace       60454;
    }
    Top
    {
        type            wall;
        inGroups        1(wall);
        nFaces          61;
        startFace       60515;
    }
)
alpha.liquid (Volume fraction of liquid)
Code:
dimensions      [0 0 0 0 0 0 0];

internalField   uniform 1;

boundaryField
{
    Bottom
    {
        type            zeroGradient;
    }

    Top
    {
        type            zeroGradient;    
    }

    Left
    {
        type            zeroGradient;
    }

    Right
    {
        type            zeroGradient;
    }

    FrontandBack
    {
        type            empty;
    }
}
The initial pressure is 1 atm, temperature 20C. The saturation temperature is given fixed at 100C to simplify the problem. Turbulence is modelled by a k-wSST model. All the walls are at a temperature of 110C, so phase change occurs quickly.

All the turbulence fields (epsilon, omega, nut, k) have boundary conditions respecting the wallFunction function (epsilonWallFunction, nutWallFunction etc). p and p_rgh have zeroGradient boundaries. U has noSlip and T, as I said, have a 110 C fixedValue.



As the simulation progresses, the liquid water close to the walls turns into gas which rises to the top of the tank by gravity. After a while, there is not even any liquid left and the gas continues to heat up to 110C. But I have a major problem: the pressure inside the enclosed enclosure do not rise which is not possible when considering the conservation of matter at constant volume.

In fact I noticed that the pressure reaches pRefValue whatever the boundaries. I've tried to change the boundaries in many different ways, there is almost no influence on the pressure, which just goes from initial pressure to pRefValue.

According to the source code of interCondensatingEvaporatingFoam, this therefore means that my simulation lacks data allowing it to operate without clinging to the pRefValue. But I can't find what. Does someone have an idea ? I feel like the problem is not even with file 0, nor in transportProperties...

Thank you !
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multiphase, phase_change, prefvalue, pressure

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