[dduon101]

Hello all,

I wanted to ask how one would get the heat flux across the cylindrical wall of a tube (patch). I have looked at the forums and tried the method posted in:

Calculate flux across surface

Additionally, I looked at the following to gain an understanding and try to modify it for heat flux, but as a C++ beginner at programming, I have no idea what I'm supposed to do.

https://openfoamwiki.net/index.php/S...ting_mass_flow

I would like to be able to use the controlDict method, if possible. Please note that I am using OpenFOAM 2.2.2. Thank you.

[jherb]

You can use the wallHeatFlux function object. See:
https://www.openfoam.com/documentati...lHeatFlux.html
https://github.com/OpenFOAM/OpenFOAM...wallHeatFlux.H


For the OpenFOAM-2.2 see: https://github.com/OpenFOAM/OpenFOAM...wallHeatFlux.C

[dduon101]

Thank you very much! I will take a look and try it out!

[dduon101]

Sorry to bother again, but when I followed the guide I got the following error when I wrote the wallHeatFlux under the functions subdictionary in the controlDict file.

functions
{
wallHeatFlux1
{
// Mandatory entries (unmodifiable)
type wallHeatFlux;
libs (fieldFunctionObjects);

patches (sides);
qr qr;
}
}

The error I get is:

Unknown function type wallHeatFlux

Valid functions are :

20
(
cellSource
faceSource
fieldAverage
fieldCoordinateSystemTransform
fieldMinMax
fieldValueDelta
nearWallFields
patchProbes
patchRtis
probes
processorField
readFields
regionSizeDistribution
rtis
sets
streamLine
surfaceInterpolateFields
surfaces
turbulenceFields
wallBoundedStreamLine
)

I'm not sure what to do here. Thanks for the help!

[jherb]

It looks like the funciton object is not available in 2.2 version. The wallHeatFlux is a post processing utility, which has to be called after the run and will work with the stored values in the time folders.



Or you can try to backport the function object. But I do not know how much work this would be.

[dduon101]

Hello again! Thanks for the help as always. I will try to see what I can do regarding the backporting of the function object. If you know a good starting point to explore, that would be great! If not, I'll try to slug through it!

[stater]

Greetings foamers,

We are working on the case where we have a fluid circuling around a heat exchangers,so we are trying to calculate the heat flux through the boundary between the fluid and the solid: we use for that wallHeatFlux funciton.

The Integral value in the file "postprocessing/Region/WallHeatFlux/0/wallHeatFlux.dat" given by wallHeatFlux function, is it calculated by:

(Heatflux value on each point) x (Surface of the cell face).

or

( (Heatflux value on each point)) x (Total surface).

Thanks a lot.