[JohnMB]

I am having difficulties with the proper region to region boundaries using chtMultregionfoam. for heat transfer



To test I made a very simple model with 3 regions, in a stack, with the top boundary held at 800 and the bottom a symmetry plane. The middle region(buildBlock) has a high thermal conductivity compared to the upper (heater) and lower(filledVolume).


What I see is that the heat flux between the top and middle is very low, the high conductivity region is acting as a thermal barrier!

I'm assuming that I have set up the boundaries incorrectly somehow.


This is from the changeDictionaryDict of the top layer

T
{
internalField uniform 300;

boundaryField
{
".*"
{
type zeroGradient;
value uniform 300;
}
heater_to_buildBlock
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
Tnbr T;
kappaMethod solidThermo;
value uniform 300;
}
maxY{
type fixedValue;
value uniform 800;
}

}
}

The only difference in the thermophysical properties between the regions is in the value of kappa, which s 5 for the upper an lower regions and 50 for the middle region.

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

mixture
{
specie
{
molWeight 12;
}

transport
{
kappa 5;
}

thermodynamics
{
Hf 0;
Cp 500;
}

equationOfState
{
rho 8000;
}
}

Can anyone suggest what i am getting wrong?