View Issue Details

IDProjectCategoryView StatusLast Update
0001369OpenFOAMBugpublic2014-12-29 11:09
Reporteruser700Assigned Tohenry  
Status resolvedResolutionfixed 
Summary0001369: turbulentTemperatureRadCoupledMixedFvPatchScalarField::updateCoeffs(): refValue can become negative
DescriptionIn turbulentTemperatureRadCoupledMixedFvPatchScalarField::updateCoeffs()
a field alpha is computed as KDeltaNbr - (Qr + QrNbr)/Tp, which can become negative, if Qr is large, and results in a negative refValue later. This is passed to a thermo.He() function as a temperature in enthalpy based solver, leading to a crash. (Or to nonsensical calculations of enthalpy as function of temperature).
I propose to include the radiative contribution in the refGrad instead, as refGrad=(Qr+QrNbr)/kappa. I did this and my case where I ran into this problem is working fine now.
TagsNo tags attached.



2014-08-08 12:33


I forgot to mention: The trouble really arises with temperature dependent heat capacities ...


2014-08-11 09:23


Could you provide a simple case for testing?


2014-08-11 11:06


Might take a week because I wont be here but I will try to set up a case based on the tutorial files.


2014-08-13 14:29


Found an easy way to reproduce this:

I am using OpenFoam 2.2.x, but as far as I see it should be the same with 2.3.

1.) Take tutorial case multiRegionHeaterRadiation
2.) change constant/heater/thermophysicalProperties to this:

    type heSolidThermo;
    mixture pureMixture;
    //transport constIso;
    transport polynomial;
    //thermo hConst;
    thermo hPolynomial;
    equationOfState rhoConst;
    specie specie;
    energy sensibleEnthalpy;

        nMoles 1;
        molWeight 12;

        //kappa 80;
    kappaCoeffs<8> (80 0 0 0 0 0 0 0);

        Hf 0;
    Sf 0.;
        // Cp 450;
    CpCoeffs<8> (200 0.6 0 0 0 0 0 0);

        rho 8000;

3.) change the boundary condition in 0/heater/T for minY from fixedValue 300 to fixedValue 1500

4.) run chtMultiRegionSimpleFoam and at t=374 this will (hopefully :) happen:
Maximum number of iterations exceeded

    From function thermo<Thermo, Type>::T(scalar f, scalar T0, scalar (thermo<Thermo, Type>::*F)(const scalar) const, scalar (thermo<Thermo, Type>::*dFdT)(const scalar) const, scalar (thermo<Thermo, Type>::*limit)(const scalar) const) const
5.) change in updateCoeffs() to:
    valueFraction() = KDeltaNbr/(KDeltaNbr+KDelta);
    refValue() = TcNbr;
    refGrad() = (Qr+QrNbr)/kappa(*this);

run again, for me it works, then.


2014-08-26 12:14


To be a little more precise: I think here Tw.refValue() should really evaluate to a temperature, not some effective value, because it is passed to the thermo to calculate the enthalpy:

void Foam::mixedEnergyFvPatchScalarField::updateCoeffs()
    if (updated())

    const basicThermo& thermo = basicThermo::lookupThermo(*this);
    const label patchi = patch().index();

    const scalarField& pw = thermo.p().boundaryField()[patchi];
    mixedFvPatchScalarField& Tw = refCast<mixedFvPatchScalarField>


    valueFraction() = Tw.valueFraction();
    refValue() = thermo.he(pw, Tw.refValue(), patchi);
    refGrad() =
        thermo.Cpv(pw, Tw, patchi)*Tw.refGrad()
      + patch().deltaCoeffs()*
            thermo.he(pw, Tw, patchi)
          - thermo.he(pw, Tw, patch().faceCells())



2014-12-29 11:09

manager   ~0003375

Thanks for the bug-report and analysis of the problem. I have now studied the issue carefully and reproduced the problem in OpenFOAM-2.3.x based on your suggestion but I had to significantly increase the heater temperature to cause a crash.

As you suggest there are two actually two issues, one relating to a potential failure if Qr+QrNbr causes the reference temperature to become negative and the second relating to the local-linearization used in the T->h->T boundary condition conversions which requires the reference temperature to be close to the boundary temperature in the case of non-linear properties. Both of these issues are resolved by your suggested fix:

    valueFraction() = KDeltaNbr/(KDeltaNbr+KDelta);
    refValue() = TcNbr;
    refGrad() = (Qr+QrNbr)/kappa(*this);

which I have applied to OpenFOAM-2.3.x and OpenFOAM-dev.

Resolved by commit a01b5bb4a064656d07825359784fa34424c2b894

Issue History

Date Modified Username Field Change
2014-08-07 14:16 user700 New Issue
2014-08-08 12:33 user700 Note Added: 0003199
2014-08-11 09:23 user21 Note Added: 0003201
2014-08-11 11:06 user700 Note Added: 0003202
2014-08-13 14:29 user700 Note Added: 0003203
2014-08-26 12:14 user700 Note Added: 0003220
2014-12-29 11:09 henry Note Added: 0003375
2014-12-29 11:09 henry Status new => resolved
2014-12-29 11:09 henry Resolution open => fixed
2014-12-29 11:09 henry Assigned To => henry