Butterfly Heat Flux

Very often a surface temperature is not know - internal environment studies for example - but a heat flux is required. This could be a W/m2 or W/m3 but is there still no easy way to incorporate this within my Butterfly model? If needs be I could edit the files in the project folder if someone could advise me how!

Thanks very much!

Hi @EwanF,

Welcome to the forum, please use a profile picture.

You can modify your boundary condition in the /0 folder, edit the T file and use heat flux boundary condition to input w/m2 (input value as X):

type externalWallHeatFluxTemperature;
mode flux;
q uniform X
value $internalField;

Keep us posted of your results with illustrations and description please.


Hi @OlivierDambron
The method that you used is nice. But I just want to do this in butterfly. So is there any custom python script for setting heat flux?

Hi,@OlivierDambron I have followed your setting and run the simple_HVAC example.But blueCore-CFD gived me some error about this.Would you like to tell me how to set heat flux correctly for this examole?
The folder i 0/T.
The error of blueCFD-core

Hi @minggangyin,
here it is, please post some results of what you are doing if it works.


    type        externalWallHeatFluxTemperature;
    mode        flux;
    q           uniform 33; 
    kappaMethod fluidThermo;
    value       $internalField;


@OlivierDambron I try to add kapperMethod fluidThermo to T file. After running,blueCFD has another error:
kappaMethod defined to employ fluidThermo method, but thermo package not available
Would you like to share the successfull fold of Openfoam using heat flux ?

$ buoyantBoussinesqSimpleFoam
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: 5.x |
| \ / A nd | Web: www.OpenFOAM.org |
| \/ M anipulation | |
Windows 32 and 64 bit porting by blueCAPE: http://www.bluecape.com.pt
| Based on Windows porting (2.0.x v4) by Symscape: http://www.symscape.com |
Build : 5.x-963176928289
Exec : C:/PROGRA~1/BLUECF~1/OpenFOAM-5.x/platforms/mingw_w64GccDPInt32Opt/bin/buoyantBoussinesqSimpleFoam.exe
Date : Feb 12 2020
Time : 09:30:09
PID : 22044
I/O : uncollated
Case : C:/Users/minggang/butterfly/simple_hvac
nProcs : 1
SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

SIMPLE: no convergence criteria found. Calculations will run for 1000 steps.

Reading thermophysical properties

Reading field T

Reading field p_rgh

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Creating turbulence model

Selecting turbulence model type RAS
Selecting RAS turbulence model RNGkEpsilon
RASModel RNGkEpsilon;
turbulence on;
printCoeffs on;
Cmu 0.0845;
C1 1.42;
C2 1.68;
C3 0;
sigmak 0.71942;
sigmaEps 0.71942;
eta0 4.38;
beta 0.012;

Reading field alphat

Reading g

Reading hRef
Calculating field g.h

No MRF models present

Radiation model not active: radiationProperties not found
Selecting radiationModel none
No finite volume options present

Starting time loop

Time = 1

smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.06911466, No Iterations 3
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.04839663, No Iterations 3
smoothSolver: Solving for Uz, Initial residual = 1, Final residual = 0.05782475, No Iterations 4

kappaMethod defined to employ fluidThermo method, but thermo package not available

From function Foam::tmp<Foam::Field<double> > Foam::temperatureCoupledBase::kappa(const scalarField&) const
in file turbulentFluidThermoModels/derivedFvPatchFields/temperatureCoupledBase/temperatureCoupledBase.C at line 171.

FOAM exiting

hi @minggangyin

I think this issue has to do with the solver for incompressible fluid that you are using “buoyantBoussinesqSimpleFoam”. I don’t know enough about the kappa variable so as to give you better information, although I think the externalWallHeatFluxTemperature boundary condition works exclusively with compressible solvers and I managed to run it using buoyantSimpleFoam on openfoam v7 for ubuntu.

Keep us posted.

Hi, I have this error too. my problem is simulation of wind flow with considering heat transfer around buildings in urban area and I am using buoyantBossinesqueSimpleFoam Solver. then if externalWallHeatFluxTemperature is only for compressible flows, what is similar condition for incompressible? thanks