[Sedullo]

I need to know what is the thermal conductivity value of my simulation. I am simulating a natural convection problem using buoyantPimpleFoam, but I do not know where to read k (thermal conductivity).

Is it somewhere in the thermophysical properties?

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      thermophysicalProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

thermoType
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleEnthalpy;
}

pRef            101325;

mixture
{
    specie
    {
	nMoles          1;
        molWeight       28.9;
    }
    thermodynamics
    {
        Cp              1006.591;
        Hf              0;
    }
    transport
    {
        mu              1.85e-5;
        Pr              0.7;
    }
}


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

[fumiya]

Hi,

You might want to check the definition of the Prandtl number (Pr):
https://en.wikipedia.org/wiki/Prandtl_number

The thermal conductivity k is uniquely identified because the values of mu, Cp and Pr are specified.

Hope this helps,
Fumiya

[Sedullo]

Originally Posted by fumiya

Hi,

You might want to check the definition of the Prandtl number (Pr):
https://en.wikipedia.org/wiki/Prandtl_number

The thermal conductivity k is uniquely identified because the values of mu, Cp and Pr are specified.

Hope this helps,
Fumiya

Hi Fumiya,

That was so helpful! I understood that the value of k that I was using was wrong because I changed mu in my simulation.

Then I have another question, what about the Thermal Expansion (Beta)? what are the parameter which affect the value?

I ask that because I need it to calculate the Grashof number

[fumiya]

Hi Sedullo,

For a perfect gas, the thermal expansion is a inverse of the absolute temperature:
https://en.m.wikipedia.org/wiki/Thermal_expansion

Hope this helps,
Fumiya

[hiuluom]

Originally Posted by fumiya

Hi,

You might want to check the definition of the Prandtl number (Pr):
https://en.wikipedia.org/wiki/Prandtl_number

The thermal conductivity k is uniquely identified because the values of mu, Cp and Pr are specified.

Hope this helps,
Fumiya

Hi Fumiya,

If the vicous is sutherland law, does it has relation between k, As, Ts?