[guserik]

Hello
I got a really frustrating problem. I have established a procedure for simulating conjugated heat transfer between fluid and solid with chtMultiRegionSimpleFoam. My models have always worked but now when i have a really fine model everything crash after around 600 iterations. Until this the solution converge good and the all residuals are less than 0.001. Is there anyone who knows how to solve this problem?

[akidess]

http://www.cfd-online.com/Forums/ope...-get-help.html

[guserik]

My mesh seems ok when i runned the checkMesh. Since i run it on our cluster i dont get t

Time = 585

Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 0.0002279771, Final residual = 7.889007e-06, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.0003652472, Final residual = 9.324946e-06, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.001360254, Final residual = 3.218115e-05, No Iterations 1
GAMG:  Solving for h, Initial residual = 0.0004399999, Final residual = 9.285599e-07, No Iterations 2
Min/max T:337.9997 341.8999
GAMG:  Solving for p_rgh, Initial residual = 0.002022551, Final residual = 1.222316e-05, No Iterations 5
GAMG:  Solving for p_rgh, Initial residual = 0.0005562866, Final residual = 5.387977e-06, No Iterations 3
time step continuity errors : sum local = 0.0563915, global = -8.993817e-05, cumulative = -62.71551
Min/max rho:1054 1054
DILUPBiCG:  Solving for epsilon, Initial residual = 0.0849624, Final residual = 0.0002585619, No Iterations 1
bounding epsilon, min: -26.73187 max: 15466.52 average: 2.532161
DILUPBiCG:  Solving for k, Initial residual = 0.00134489, Final residual = 1.96022e-05, No Iterations 1
Solving for solid region solid
DICPCG:  Solving for h, Initial residual = 0.0003222915, Final residual = 9.867308e-06, No Iterations 2
DICPCG:  Solving for h, Initial residual = 0.0003249724, Final residual = 1.023341e-05, No Iterations 2
Min/max T:min(T) [0 0 0 1 0 0 0] 338 max(T) [0 0 0 1 0 0 0] 346.6688
ExecutionTime = 3132.69 s  ClockTime = 3139 s
Time = 586

Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 0.01086879, Final residual = 4.23718e-09, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.1005754, Final residual = 1.090088e-08, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.176239, Final residual = 1.885607e-08, No Iterations 1
GAMG:  Solving for h, Initial residual = 0.1106389, Final residual = 0.001035424, No Iterations 1
Min/max T:337.9997 341.9038
GAMG:  Solving for p_rgh, Initial residual = 0.002115051, Final residual = 2.05201e-05, No Iterations 5
GAMG:  Solving for p_rgh, Initial residual = 0.9963446, Final residual = 0.004556654, No Iterations 8
time step continuity errors : sum local = 13971.99, global = -10.3378, cumulative = -73.05331
Min/max rho:1054 1054
DILUPBiCG:  Solving for epsilon, Initial residual = 0.3303189, Final residual = 0.01969804, No Iterations 1
bounding epsilon, min: -22.85394 max: 36519.9 average: 2.713533
DILUPBiCG:  Solving for k, Initial residual = 0.9996548, Final residual = 0.008013062, No Iterations 1
Solving for solid region solid
DICPCG:  Solving for h, Initial residual = 0.0003217334, Final residual = 9.850451e-06, No Iterations 2
DICPCG:  Solving for h, Initial residual = 0.0003244086, Final residual = 1.021595e-05, No Iterations 2
Min/max T:min(T) [0 0 0 1 0 0 0] 338 max(T) [0 0 0 1 0 0 0] 346.6729
ExecutionTime = 3138.66 s  ClockTime = 3145 s
Time = 587

Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 0.2542555, Final residual = 0.003127732, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.229307, Final residual = 0.001091918, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.3299211, Final residual = 0.001057152, No Iterations 1
GAMG:  Solving for h, Initial residual = 0.9999995, Final residual = 0.001948424, No Iterations 3
Min/max T:-1.192378e+07 3671610
GAMG:  Solving for p_rgh, Initial residual = 0.9833382, Final residual = 0.004657309, No Iterations 20
GAMG:  Solving for p_rgh, Initial residual = 0.5844197, Final residual = 0.003799768, No Iterations 4
time step continuity errors : sum local = 89309.59, global = -30.79077, cumulative = -103.8441
Min/max rho:1054 1054
DILUPBiCG:  Solving for epsilon, Initial residual = 0.9930006, Final residual = 0.0390609, No Iterations 2
bounding epsilon, min: -25.73662 max: 6.531648e+09 average: 41468.83
DILUPBiCG:  Solving for k, Initial residual = 0.999766, Final residual = 0.01822295, No Iterations 2
Solving for solid region solid
DICPCG:  Solving for h, Initial residual = 0.01450694, Final residual = 0.0007850409, No Iterations 2
DICPCG:  Solving for h, Initial residual = 0.01102243, Final residual = 0.0005736408, No Iterations 2
Min/max T:min(T) [0 0 0 1 0 0 0] -669.9338 max(T) [0 0 0 1 0 0 0] 13726.58
ExecutionTime = 3146.34 s  ClockTime = 3152 s
Time = 588

Solving for fluid region fluid
DILUPBiCG:  Solving for Ux, Initial residual = 0.2112948, Final residual = 0.001279738, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.1900647, Final residual = 0.001276108, No Iterations 1
DILUPBiCG:  Solving for Uz, Initial residual = 0.2537446, Final residual = 0.0007415269, No Iterations 1
GAMG:  Solving for h, Initial residual = 0.6227222, Final residual = 0.0004394558, No Iterations 2
[15] 
[15] --> FOAM FATAL ERROR: 
[15] Maximum number of iterations exceeded
[15] 
[15]     From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
[15]     in file /disk/sw/OpenFOAM/OpenFOAM-2.2.2/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 76.
[15]

After this step i got the error message Maximal number of iterations exceeded.

My fv solution is

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
solvers
{
    rho
    {
        solver          PCG
        preconditioner  DIC;
        tolerance       1e-7;
        relTol          0;
    }
    p
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-06;
        relTol          0.01;
    }
    U
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-05;
        relTol          0.1;
    }
    p_rgh
    {
        solver           GAMG;
        tolerance        1e-7;
        relTol           0.01;
        smoother         GaussSeidel;
        cacheAgglomeration true;
        nCellsInCoarsestLevel 10;
        agglomerator     faceAreaPair;
        mergeLevels      1;
        maxIter          100;
    }
    h
    {
        solver           GAMG;
        tolerance        1e-7;
        relTol           0.01;
        smoother         GaussSeidel;
        cacheAgglomeration true;
        nCellsInCoarsestLevel 10;
        agglomerator     faceAreaPair;
        mergeLevels      1;
        maxIter          100;
    }
    k
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-05;
        relTol          0.1;
    }
    epsilon
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-05;
        relTol          0.1;
    }
    R
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-05;
        relTol          0.1;
    }
    "(k|epsilon)"
    {
        solver           PBiCG;
        preconditioner   DILU;
        tolerance        1e-7;
        relTol           0.1;
    }
}
SIMPLE
{
    momentumPredictor on;
    nNonOrthogonalCorrectors 0;
    pRefCell        0;
    pRefValue       100000;
    rhoMin          rhoMin [1 -3 0 0 0] 1054;
    rhoMax          rhoMax [1 -3 0 0 0] 1054;
}
relaxationFactors
{
    fields
    {
        rho             1;
        p_rgh           0.7;
    }
    equations
    {
        U               0.3;
        h               0.7;
        nuTilda         0.7;
        k               0.7;
        epsilon         0.7;
        omega           0.7;
        "ILambda.*"     0.7;
    }
}
// ************************************************************************* //

My fvSchemes

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
ddtSchemes
{
    default     steadyState;
}
gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         Gauss linear;
}

divSchemes
{
    default         none;
    div(phi,U)      bounded Gauss upwind;
    div(phi,K)      bounded Gauss upwind;
    div(phi,h)      bounded Gauss upwind;
    div(phi,k)      bounded Gauss upwind;
    div(phi,K)      bounded Gauss upwind;
    div(phi,epsilon) bounded Gauss upwind;
    div(phi,R)      bounded Gauss upwind;
    div(R)          Gauss linear;
    div((muEff*dev2(T(grad(U))))) Gauss linear;
}
 
 
laplacianSchemes
{
    default         none;
    laplacian(muEff,U) Gauss linear corrected;
    laplacian(Dp,p_rgh) Gauss linear corrected;
    laplacian(alphaEff,h)  Gauss linear corrected;
    laplacian(DkEff,k) Gauss linear corrected;
    laplacian(DepsilonEff,epsilon) Gauss linear corrected;
    laplacian(DREff,R) Gauss linear corrected;
}
interpolationSchemes
{
    default         linear;
    interpolate(U)  linear;
}
snGradSchemes
{
    default         corrected;
}
fluxRequired
{
    default         yes;
    p_rgh;
 T;
}

But i cant really figure out what is my problem since i runned the simulations before and then it's always converged. The only difference now is that my grid is finer and i switched properties from water to water/glycol