CFD Online Discussion Forums - Anisotropic thermal conductivity in CHT SimpleFoam

Dear all,

I am running an anisotropic thermal conductivity using chtMultiRegionSimpleFoam solver. The simulation has two solid regions. Spherical region embedded inside a hemispherical region named as tumor and gland. I have attached the case file for reference.

Thermophysical property:

1. The anisotropic thermal properties for both the regions are as mentioned below:

Code:

/*--------------------------------*- C++ -*----------------------------------*\

| =========                 |                                                 |

| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |

|  \\    /   O peration     | Version:  2.1.x                                 |

|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |

|    \\/     M anipulation  |                                                 |

\*---------------------------------------------------------------------------*/

FoamFile

{

    version     2.0;

    format      ascii;

    class       dictionary;

    object      solidThermophysicalProperties;

}

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





thermoType

{

    type            heSolidThermo;

    mixture         pureMixture;

        transport       constAnIso;

    //transport       constIso;

    thermo          hConst;

    equationOfState rhoConst;

    specie          specie;

    energy          sensibleEnthalpy;

}



coordinateSystem 

{

    type    cartesian;  // global co-ordinate system (redundant)

    origin  (0.006713780918727913 0.032 -0.006082474226804117);   

    coordinateRotation

    {

        type    cylindrical; // local Cartesian co-ordinates

        //e3      (0 0 0);

        e3      (0 0 1); // axis of rotation

    }

}



mixture

{

    specie

    {

      molWeight   0;

    }



    transport

    {

                kappa   (0.48 0.1 0.1);

        //kappa   0.51;

    }



    thermodynamics

    {

        Hf      0;

        Cp      3770;

    }



    equationOfState

    {

        rho     1050;

    }

}



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

Problem:

1. From the above thermophysical property, I could understand that the heat will flow radially since it has mode kappa value and directed along the z axis of rotation.

2. Based on this understanding, I expect my resulting simulation such that the heat from the internal sphere should move upwards (y coordinate in design) acting as a source. The outer boundary is impemented with convection BC with an ambient temperature of 22, while the spherical tumor source is having initial temperature of 38. The simulation is steady state.

But, in my simulation, the heat is moving downwards as it can be seen after the simulation in the image presented below. I tried the axis values with (-1) and also with other direction like tangential kappa.

What is wrong in my thermophysical properties as such?

I have attached the complete project file in a zip.

Simulation image after 100 iterations.

https://drive.google.com/file/d/1SaR...ew?usp=sharing

Zip_file link

https://drive.google.com/file/d/1WVh...ew?usp=sharing

1. The file is of size 84 MB. Please run and provide if anything missing.

2. The mesh has been run, please run "chtMultiRegionSimpleFoam" and create all.foam later on to check the results.

Please feel free to check other boundary conditions also and provide feedback so that I can improve upon the problem.

Regards,
Sunag R A.