[KKlee]

Hi, Foamers,
I encountered a non converged problem when I used chtMultiRegionFoam for a steadystate solution.

The geometry is shown as the attached geometry picture，except for the hydrogen flow channel, the others are solid structures. when I set the Hydrogen density as constant, the case runs well, but when I changed it to a polynominal formal, the case will crashed because of the negative temperature. (For simplicity, I did not turn on the heat source)
fvScheme fvSolution and thermalProperties settings of Hydrogen are as following:
fvScheme:

ddtSchemes
{
    default         Euler;
}

gradSchemes
{
    default         Gauss linear;
}

divSchemes
{
    default         none;


    div(phi,U)      Gauss linearUpwind grad(U);
    div(phi,h)      Gauss limitedLinear 1;
    turbulence      Gauss limitedLinear 1;
    div(phi,k)      $turbulence;
    div(phi,epsilon) $turbulence;
    div(phi,omega) $turbulence;
    div(phi,K) $turbulence;

    div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear limited 0.5;
    //laplacian((rho*nuEff),U)    Gauss linear corrected;
    //laplacian(alphaEff,h)       Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
}

wallDist
{
    method meshWave;
}

fvSolution:

solvers
{
    rho
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-7;
        relTol          0.1;
    }

    rhoFinal
    {
        $rho;
        tolerance       1e-7;
        relTol          0;
    }

    p_rgh
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-8;
        relTol          0.01;

    }
/*
    p_rgh
    {
        solver           GAMG;
        tolerance        1e-7;
        relTol           0;

        smoother         GaussSeidel;

    }


    p_rgh
    {
        solver           PCG;
        preconditioner
	{
        preconditioner	GAMG;
        tolerance        1e-7;
        relTol           0;
	nVcycles 	 2;
        smoother         DICGaussSeidel;
	nPreSweeps	2;
	nPostSweeps	2;
	nFinestSweeps	2;
        cacheAgglomeration true;
        nCellsInCoarsestLevel 10;
        agglomerator    faceAreaPair;
        mergeLevels     1;	
	}
        tolerance        1e-7;
        relTol           0;
        maxIter          100;
    }
*/
    p_rghFinal
    {
        $p_rgh;
        tolerance        1e-7;
        relTol           0;
    }
    "(U|h|k|epsilon|R)"
    {
        solver           PBiCGStab;
        preconditioner   DILU;
        tolerance        1e-7;
        relTol           0.1;
    }

    "(U|h|k|epsilon|R)Final"
    {
        $U;
        tolerance        1e-7;
        relTol           0;
    }
}

PIMPLE
{
    momentumPredictor   yes;
    nCorrectors         4;
    nNonOrthogonalCorrectors 2;
    rhoMax          57.26;
    rhoMin          0.348388;
    pRefCell          0;
    pRefValue         4e6;
}

relaxationFactors
{
    equations
    {
        "h.*"           1;
        "U.*"           0.7;
    }
    fields
    {
        rho             1;
        p_rgh           0.3;
    }
}
}

thermalproperties:

thermoType
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       polynomial;
    thermo          hPolynomial;
    equationOfState icoPolynomial;
    specie          specie;
    energy          sensibleEnthalpy;
}


mixture
{
    // coefficients for Hydrogen

    specie
    {
        molWeight       2;
    }
    equationOfState
    {
     //   rhoCoeffs<8>    ( 2 0 0 0 0 0 0 0 );
        rhoCoeffs<8>    ( 2.028571 -0.000029 0 0 0 0 0 0 );
    }
    thermodynamics
    {
        Hf              0;
        Sf              0;
        CpCoeffs<8>     ( 19304 -21.912 3.3433e-2 -2.1053e-5 5.8506e-9 -5.4377e-13 0 0 );
    }
    transport
    {
        muCoeffs<8>     ( 4.3563e-6 1.3319e-8 -2.0504e-12 3.2893e-16 -1.5746e-20 0 0 0 );
        kappaCoeffs<8>  ( 0.21475  -4.5995e-4 1.2216e-6 -6.9773e-10 1.3786e-13 0 0 0 );
    }
}

The 0 and log files are provided in the attached zone.
Any comments or suggestions are welcome since I've been stuck here for too long. Thanks in advance.
lee

[lonewanderer]

Hi Lee,

1. Check if you defined interfaces correctly. Because after seeing your log file i observed that there are missing interfaces.

2. Please also check boundary conditions.
3. Turn off functions inside controlDict.