[piu58]

Dear CFDlers,

I hope you enjoy your christmas as I do.

I have a question with buoyantPimpleFoam. I think I resolve it some day. But may be, somebody knows a solution faster.

I simulate the mass transfer of a component which is active at a surface (electroplating). Instead of concentration (which I need to know) I use temperature: The equations are the same. buoyantPimpleFoam is suitable for this.

In the first step I calculated something with forced convection, a flow from a pump is directed to the surface (electrode). The results look fine. I use a temperature of 0 at the surface (all of the content of chemicals is consumed there) and a temperature (in my case concentration) of 1 in the inner of the fluid. The "1" represents the concentration of the free flow / main volume.

~

A more complicated case is the free convection: The flow is driven by the density difference. At the surroundings of the surface the fluid is lighter because one if the ingredient is removed by the reaction.

I first changed my simulation only in one detail. In the thermophysical properties I change

thermoType
{
:
     equationOfState rhoConst;
}

mixture {
        rho             1200; // Dichte
    }
}

to

thermoType {
:
    equationOfState perfectGas;
}

mixture {
:
    equationOfState  {
	rhoCoeffs<8> (1200 0 0 0 0 0 0 0);
    }
}

From my point of view this should change nothing: The density is constant 1200 kg/m³. In reality I would use

	rhoCoeffs<8> (1000 200 0 0 0 0 0 0);

which means at c=0 the density is the one of pure water, and with the chemical in it it is 20% higher.

The simulation runs fine with rhoConst. It crashes with perfectGas:

:
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
PIMPLE: iteration 1
DILUPBiCG:  Solving for Ux, Initial residual = nan, Final residual = nan, No Iterations 1001
DILUPBiCG:  Solving for Uy, Initial residual = nan, Final residual = nan, No Iterations 1001
DILUPBiCG:  Solving for h, Initial residual = nan, Final residual = nan, No Iterations 1001
GAMG:  Solving for p_rgh, Initial residual = nan, Final residual = nan, No Iterations 1000
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = nan, global = nan, cumulative = nan
GAMG:  Solving for p_rgh, Initial residual = nan, Final residual = nan, No Iterations 1000


--> FOAM FATAL IO ERROR:
wrong token type - expected Scalar, found on line 0 the word 'nan'

Does somebody of you know what mistake I made?

Thank you for your help, Uwe.


The complete log:

buoyantPimpleFoam
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  3.0.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
|*---------------------------------------------------------------------------*|
|* OpenFOAM for Windows 17.02 (v1)                                           *|
|* Built by CFD Support, www.cfdsupport.com (based on Symscape).             *|
\*---------------------------------------------------------------------------*/
Build  : 3.0.x-495c0feff174
Exec   : C:\OpenFOAM\17.02\cygwin64\opt\OpenFOAM\OpenFOAM-3.0.x\platforms\cygwin64mingw-w64DPInt32Opt\bin\buoyantPimpleFoam.exe
Date   : Dec 24 2017
Time   : 07:38:44
Host   : "ALBIREO"
PID    : 9392
Case   : C:/OpenFOAM/17.02/uwe-3.0.x/run/AHull2dFreieKonvektion
nProcs : 1
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

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

Create mesh for time = 0


PIMPLE: max iterations = 100
    field "(p|U|k|epsilon)"     : relTol 0, tolerance 0.01

Reading thermophysical properties

Selecting thermodynamics package
{
    type            heRhoThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleEnthalpy;
}

Reading field U

Reading/calculating face flux field phi

Creating turbulence model

Selecting turbulence model type laminar

Reading g

Reading hRef
Calculating field g.h

Reading field p_rgh

Creating field dpdt

Creating field kinetic energy K

No MRF models present

No finite volume options present

Radiation model not active: radiationProperties not found
Selecting radiationModel none
Courant Number mean: nan max: nan

Starting time loop

Courant Number mean: nan max: nan
deltaT = 0.00119048
Time = 0.00119048

diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
PIMPLE: iteration 1
DILUPBiCG:  Solving for Ux, Initial residual = nan, Final residual = nan, No Iterations 1001
DILUPBiCG:  Solving for Uy, Initial residual = nan, Final residual = nan, No Iterations 1001
DILUPBiCG:  Solving for h, Initial residual = nan, Final residual = nan, No Iterations 1001
GAMG:  Solving for p_rgh, Initial residual = nan, Final residual = nan, No Iterations 1000
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = nan, global = nan, cumulative = nan
GAMG:  Solving for p_rgh, Initial residual = nan, Final residual = nan, No Iterations 1000


--> FOAM FATAL IO ERROR:
wrong token type - expected Scalar, found on line 0 the word 'nan'

file: C:/OpenFOAM/17.02/uwe-3.0.x/run/AHull2dFreieKonvektion/system/data.solverPerformance.p_rgh at line 0.

    From function operator>>(Istream&, Scalar&)
    in file lnInclude/Scalar.C at line 93.

FOAM exiting

[piu58]

I found a solution by myself. Instead of changing the behavior of rho only I switched to the all polynomial formulation:

thermoType {
    type            heRhoThermo;
    mixture         pureMixture;
    transport       polynomial;
    thermo          hPolynomial;
    equationOfState icoPolynomial;
    specie          specie;
    energy          sensibleEnthalpy;
}

I cannot use the Prandtl (Schmidt) number anymore, but have to get the thermal conductivity. Two keep thinking in Pr, simply use