[fxzf]

Hello,

Does anyone know what is major difference between the following three heat transfer boundary conditions?

externalWallHeatFluxTemperature
compressible::turbulentTemperatureRadCoupledMixed
compressible::turbulentTemperatureCoupledBaffleMix ed

Is it possible to use externalWallHeatFluxTemperature in multi-region conjugate heat transfer at border between solid and fluid?

Thanks very much.

[Bloerb]

compressible::turbulentTemperatureRadCoupledMixed
compressible::turbulentTemperatureCoupledBaffleMixed

These two are identical with the exception that the first one adds radiation. These are coupling conditions for multi region cases. Hence the polyMesh/boundary file must read "mappedWall" for all boundaries this is used on. They are mixed boundaries on both sides. Other possibilities to couple multi region cases are possible though. In foam-extend there is an block coupled approach for example.

externalWallHeatFluxTemperature

This one has can operate in several modes. It can set a heat flux, flux/m² or an heat transfer coefficient and ambient temperature. Using this on a coupled patch is not wise as it does not couple the regions. You should instead use the above. If you want to use this at the border between a fluid without actually simulating the surrounding region it is the choice you should use.

There are also fvOption conditions to couple regions via their volume and not their boundary. For example useful if you want to simulate a heat exchanger without meshing thousands of interlocking pipes. You could instead couple them via a porosity and a function object.