[vainilreb]

Hey,

I set up a case with a small ammonia cloud in a room with an air inlet and an air outlet. The simulation runs for a few steps and then the gas temperature difference increases unreasonably fast. Maybe you can tell me why?

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.4 |
| \\ / A nd | Web: http://www.openfoam.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

FoamFile
{
version 2.0;
format ascii;
root "";
case "";
instance "";
local "";
class volScalarField;
object p;
}

// ************************************************** *********************** //

dimensions [ 1 -1 -2 0 0 0 0 ];

internalField uniform 101300;

boundaryField
{
inlet
{
type zeroGradient;
}

outlet
{
type fixedValue;
value uniform 101300;
}

walls
{
type zeroGradient;
}

empty
{
type zeroGradient;
}

// ************************************************** *********************** //

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.4 |
| \\ / A nd | Web: http://www.openfoam.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

FoamFile
{
version 2.0;
format ascii;
root "";
case "";
instance "";
local "";
class volVectorField;
object U;
}

// ************************************************** *********************** //

dimensions [ 0 1 -1 0 0 0 0 ];

internalField uniform ( 0 0 0 );

boundaryField
{
inlet
{
type fixedValue;
value uniform ( 1 0 0 );
}

outlet
{
type zeroGradient;
}

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

empty
{
type zeroGradient;
}

}

// ************************************************** *********************** //

I just a second the temperature difference increases from zero to more than 100 K... I think it's got something to do with the inlet and outlet BC. But I'm not sure WHAT.

Thanks a lot.

Robert

[vainilreb]

No idea, anyone? Changed the BC from fixedValue to inletOutlet, tried to set up fixed outlet speed and pressure-controlled inlet flow and still got the same problem.