CFD Online Discussion Forums - 0 wallHeatFlux on External Patch

I am using OpenFOAM-10 with chtMultiRegionFoam on a heat transfer problem with only solids.

The geometry of the model is given below:

Attachment 92915

I use fixed boundary conditions where T = 373 [K] on the outside edges of the model. This gives the result provided in the figure in the image below:

Attachment 92916

However, when I try to extract the heat flux at the outside edges of the model in the "system/controlDict" file using:

Code:

    wallHeatFlux1

    {

        type wallHeatFlux;

        libs ("libfieldFunctionObjects.so");

        region Cool;

        executeControl writeTime;

        executeInterval 1;

        writeControl writeTime;

        writeInterval 1;

    }

In "4e+10/Cool/wallHeatFlux", I simply get

Code:

    Sides

    {

        type            calculated;

        value           uniform 0;

    }

This is only the output for the patch on the outside edges of the model that I have labeled "Sides".

Does anyone know why this is the case? The heat flux is calculated properly on all internal surfaces and reported in "4e+10/Cool/wallHeatFlux" but is not of interest.