[amol_patel]

Hi everyone,

I am trying to a shell and tube heat exchanger case using chtMultiRegionFoam solver in OpenFoam-v2012.

I have made the mesh using snappyHexMesh and the mesh seems fine, I have three regions shell, solid and tube. In my 0 folder I have given the boundary conditions for U, T, p , p_rgh , epsilon, k, nut , rho, alphat for the shell and tube regions and for the solid region i have given T, p .along with cellToRegion for each region.

In the constant i have g, thermophysicalProperties , turbulanceProprties for shell and tube and for solid region i have thermophysicalProperties and g .

when i try to solve the case using the chtMultiRegionFoam command i get the following

amol@AMOL:~/OpenFOAM/amol-v2012/run/trial15$ chtMultiRegionFoam
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2012                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : _7bdb509494-20201222 OPENFOAM=2012
Arch   : "LSB;label=32;scalar=64"
Exec   : chtMultiRegionFoam
Date   : Oct 18 2021
Time   : 13:41:59
Host   : AMOL
PID    : 31848
I/O    : uncollated
Case   : /home/amol/OpenFOAM/amol-v2012/run/trial15
nProcs : 1
trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 5, maxFileModificationPolls 20)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create fluid mesh for region shell for time = 0

Create fluid mesh for region tube for time = 0

Create solid mesh for region solid for time = 0

*** Reading fluid mesh thermophysical properties for region shell

    Adding to thermoFluid

Selecting thermodynamics package
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState rhoConst;
    specie          specie;
    energy          sensibleEnthalpy;
}

    Adding to rhoFluid

    Adding to UFluid

    Adding to phiFluid

    Adding to hRefFluid

    Adding to ghFluid

    Adding to ghfFluid

    Adding to turbulenceFluid

Selecting turbulence model type RAS
Selecting RAS turbulence model kEpsilon
RAS
{
    model           kEpsilon;
    turbulence      on;
    printCoeffs     on;
    Cmu             0.09;
    C1              1.44;
    C2              1.92;
    C3              0;
    sigmak          1;
    sigmaEps        1.3;
}

    Adding to reactionFluid

Combustion model not active: combustionProperties not found
Selecting combustion model none
    Adding to radiationFluid

Radiation model not active: radiationProperties not found
Selecting radiationModel none
    Adding to KFluid

    Adding to dpdtFluid

    Adding to fieldsFluid

    Adding to QdotFluid

    Adding MRF

No MRF models present

    Adding fvOptions

*** Reading fluid mesh thermophysical properties for region tube

    Adding to thermoFluid

Selecting thermodynamics package
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState rhoConst;
    specie          specie;
    energy          sensibleEnthalpy;
}

    Adding to rhoFluid

    Adding to UFluid

    Adding to phiFluid

    Adding to hRefFluid

    Adding to ghFluid

    Adding to ghfFluid

    Adding to turbulenceFluid

Selecting turbulence model type RAS
Selecting RAS turbulence model kEpsilon
RAS
{
    model           kEpsilon;
    turbulence      on;
    printCoeffs     on;
    Cmu             0.09;
    C1              1.44;
    C2              1.92;
    C3              0;
    sigmak          1;
    sigmaEps        1.3;
}

    Adding to reactionFluid

Combustion model not active: combustionProperties not found
Selecting combustion model none
    Adding to radiationFluid

Radiation model not active: radiationProperties not found
Selecting radiationModel none
    Adding to KFluid

    Adding to dpdtFluid

    Adding to fieldsFluid

    Adding to QdotFluid

    Adding MRF

No MRF models present

    Adding fvOptions

*** Reading solid mesh thermophysical properties for region solid

    Adding to thermos

Selecting thermodynamics package
{
    type            heSolidThermo;
    mixture         pureMixture;
    transport       constIso;
    thermo          hConst;
    equationOfState rhoConst;
    specie          specie;
    energy          sensibleEnthalpy;
}

    Adding to radiations

Radiation model not active: radiationProperties not found
Selecting radiationModel none
    Adding fvOptions

Region: shell Courant Number mean: 0.00100823 max: 55.2758
Region: tube Courant Number mean: 0.00169429 max: 73.6277
Region: solid Diffusion Number mean: 2.42683 max: 198.736
deltaT = 4.07455e-05
Region: shell Courant Number mean: 4.10809e-06 max: 0.225224
Region: tube Courant Number mean: 6.90349e-06 max: 0.3
Region: solid Diffusion Number mean: 0.00988824 max: 0.809759
deltaT = 4.07455e-05
Time = 4.07455e-05


Solving for fluid region shell

It stops here.

I can't understand what is going wrong here.

Please help me,
Thank You,
amol.

[Bloerb]

The error message is not included, or there is none. Hence impossible to tell. Was there an error message printed to the terminal? How are you creating this file? Try this:

// might not print the error messages to the file but will display them inside the terminal
 chtMultiRegionFoam >log 


// redirects everything to the file
 chtMultiRegionFoam &>log

And post again. Or are you maybe running out of memory (not enough ram on your pc)?


And check the shell region. checkMesh -region shell. And check it's settings or post those files here. Because it crashes in that region. Hence the error is inside it.

[amol_patel]

Hi Bloerb,

I dont get any error message. So I am also confused what going on there.

i will attach the case files here so that you can check if possible also.

After i perform checkMesh -region shell i get high skewness.

amol@AMOL:~/OpenFOAM/amol-v2012/run/trial15$ checkMesh -region shell
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2012                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : _7bdb509494-20201222 OPENFOAM=2012
Arch   : "LSB;label=32;scalar=64"
Exec   : checkMesh -region shell
Date   : Oct 20 2021
Time   : 10:56:08
Host   : AMOL
PID    : 693
I/O    : uncollated
Case   : /home/amol/OpenFOAM/amol-v2012/run/trial15
nProcs : 1
trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 5, maxFileModificationPolls 20)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh shell for time = 0

Time = 0

Mesh stats
    points:           4430941
    faces:            11328582
    internal faces:   10161355
    cells:            3447313
    faces per cell:   6.23382
    boundary patches: 4
    point zones:      0
    face zones:       2
    cell zones:       3

Overall number of cells of each type:
    hexahedra:     3005180
    prisms:        127802
    wedges:        0
    pyramids:      0
    tet wedges:    134
    tetrahedra:    0
    polyhedra:     314197
    Breakdown of polyhedra by number of faces:
        faces   number of cells
            4   1466
            5   4009
            6   80520
            9   145962
           12   79018
           15   3196
           18   26

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
                   Patch    Faces   Points                  Surface topology
              shell_wall   460771   464044  ok (non-closed singly connected)
             shell_inlet      632      669  ok (non-closed singly connected)
            shell_outlet      632      669  ok (non-closed singly connected)
          shell_to_solid   705192   705476  ok (non-closed singly connected)

Checking faceZone topology for multiply connected surfaces...
                FaceZone    Faces   Points                  Surface topology
          shell_to_solid   705192   705476  ok (non-closed singly connected)
           tube_to_solid        0        0                        ok (empty)

Checking basic cellZone addressing...
                CellZone        Cells       Points       VolumeBoundingBox
                  shell      3447313      4430941   0.00247959 (-2.14509e-05 -0.045 -0.075) (0.600037 0.045 0.075)
                   tube            0            0            0 (1e+150 1e+150 1e+150) (-1e+150 -1e+150 -1e+150)
                  solid            0            0            0 (1e+150 1e+150 1e+150) (-1e+150 -1e+150 -1e+150)

Checking geometry...
    Overall domain bounding box (-2.14509e-05 -0.045 -0.075) (0.600037 0.045 0.075)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-2.91383e-16 3.41837e-17 -2.92214e-15) OK.
    Max cell openness = 4.33929e-16 OK.
    Max aspect ratio = 8.10907 OK.
    Minimum face area = 2.91661e-08. Maximum face area = 2.25294e-06.  Face area magnitudes OK.
    Min volume = 3.10002e-11. Max volume = 2.2865e-09.  Total volume = 0.00247959.  Cell volumes OK.
    Mesh non-orthogonality Max: 56.3279 average: 12.4353
    Non-orthogonality check OK.
    Face pyramids OK.
 ***Max skewness = 5.29496, 1520 highly skew faces detected which may impair the quality of the results
  <<Writing 1520 skew faces to set skewFaces
    Coupled point location match (average 0) OK.

Failed 1 mesh checks.

End

Do you think it is because of the high value of skewness that my solver crashes.

Thanks,
amol.