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-   -   gradientEnthalpy and wallHeatTransfer (http://www.cfd-online.com/Forums/openfoam-bugs/66221-gradiententhalpy-wallheattransfer.html)

markusrehm July 9, 2009 07:31

gradientEnthalpy and wallHeatTransfer
 
Hello,

I am having problems to use the gradientEnthalpy BC for buoyantSimpleFoam in the hotRoom case at the walls. For 0/T I applied it as follows:

Code:

...
fixedWalls
    {
        type            gradientEnthalpy;
        gradient        uniform -1000.0;
    }
...

It produces a memory error in the hEqn. On the other hand for the wallHeatTransfer BC everything works well.

It doesn't seem to be a problem of the thermos - so much I found out.

In gradientEnthalpyFvPatchScalarField.C:111 Tw.evaluate(); is calling its own updateCoeffs() function again and again.

Any solution to this?

I use the 1.5.x git version. See the output below.

Regards, Markus.

Code:

rem@IEC126:~/OpenFOAM/rem-1.5.x/run/buoyantSimpleFoam/hotRoom> buoyantSimpleFoam
/*---------------------------------------------------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  1.5.x                                |
|  \\  /    A nd          | Web:      http://www.OpenFOAM.org              |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
Exec  : buoyantSimpleFoam
Date  : Jul 09 2009
Time  : 13:28:26
Host  : IEC126
PID    : 529
Case  : /home/rem/OpenFOAM/rem-1.5.x/run/buoyantSimpleFoam/hotRoom
nProcs : 1

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

Create mesh for time = 0


Reading environmentalProperties
Reading thermophysical properties

Selecting thermodynamics package hThermo<pureMixture<constTransport<specieThermo<hConstThermo<perfectGas>>>>>
Reading field U

Reading/calculating face flux field phi

Creating turbulence model

Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
    Cmu            0.09;
    C1              1.44;
    C2              1.92;
    C3              0.85;
    alphah          1;
    alphak          1;
    alphaEps        0.76923;
}

Calculating field g.h

Creating field pd


Starting time loop

Time = 1

DILUPBiCG:  Solving for Ux, Initial residual = 1, Final residual = 8.16329e-07, No Iterations 6
DILUPBiCG:  Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG:  Solving for Uz, Initial residual = 1, Final residual = 8.16329e-07, No Iterations 6
Speicherzugriffsfehler


henrik July 12, 2009 14:05

Dear Markus,

The *Enthalpy-boundary conditions are not meant to be used on temperature-fields.

You can understand the internal workings by having a look into $FOAM_SRC/thermophysicalModels/basic/lnInclude/basicThermo.C

Try putting a fixedGradient boundary condition on T.

Henrik

markusrehm July 13, 2009 04:06

Thanks Henrik,

I will have a deeper look. Markus


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