CFD Online Discussion Forums - Post processing heat flow at inlet and outlet

Hello,

I am investigating a heat transfer case using buoyantSimpleFoam. The heat transfer itself is evaluated using the wallHeatFlux at the hot patches.

Additionally I would like to check the heat balance of the fluid over the inlet/outlet. To achieve that I see two ways:
1. Multiply the patch values of rho, U, he and area face wise and sum them up
2. Multiply phi, he and the area face wise and sum them up

I adjusted the solver to gain these fields.

Next I would like to adjust the post processing tool patchAverage to something like patchHeatTransfer...

My current problem is, that the original patchAverage does not work on the "he" field. I gain the error message:

Code:

    Reading volScalarField he





--> FOAM FATAL IO ERROR: 



    Cannot find 'value' entry on patch wall1 of field he in file ".../6mm-103-U-1-19821-80perc-H2O/60010/he"

    which is required to set the values of the generic patch field.

    (Actual type gradientEnergy)



    Please add the 'value' entry to the write function of the user-defined boundary-condition





file: .../6mm-103-U-1-19821-80perc-H2O/60010/he.boundaryField.wall1 from line 33693 to line 33694.



    From function genericFvPatchField<Type>::genericFvPatchField(const fvPatch&, const Field<Type>&, const dictionary&)

    in file genericFvPatchField/genericFvPatchField.C at line 71.



FOAM exiting

As far as I understand, the tool is searching the value entry at the patch "wall1", which is adiabatic by the way.

Why is it searching this entry? I do not have this problem with the rho field.

Does someone know how to solve this?