[Likun]

Dear Foamers,

As my first real exercise of code development in OpenFoam, I worked on updating the flameletFoam code (http://openfoamwiki.net/index.php/Ex...n/flameletFoam) developed by Dr. Hagen Mueller from OpenFoam-2.1.0 to OpenFoam-2.3.0. Although I really suffered a lot as a beginner, it was a nice experience anyhow. Now the new version of the flameletFoam code is working in OpenFoam-2.3.0. The code can be downloaded here:
https://sourceforge.net/projects/flameletfoam230/.

Feel free to check it.

Best,
Likun

[Likun]

Dear Foamers,

My next step is to implement FGM (Flamelet Generated Manifold) model based on the flameletFoam-2.3. Any suggestion, collaboration are very welcome!

Best,
Likun

[babakflame]

Dear Likun

Nice Try.

Have u ever checked the results of new code? I mean The code might be compiled well, however during running a case some errors might occur.

Best
Bobi

[Likun]

Dear Bobi,

Thank you!

Yes, I have run the 'pilotedDiffusionFlame' RANS tutorial case release with the original code, there is no problem, and the results is more or less the same with that given by flameletFoam-2.1. However, for the LES case, it crashes after a few time steps, and gives the following errors:

PHP Code:

[0] #0  Foam::error::printStack(Foam::Ostream&) in "/opt/apps/openfoam-2.3.0/OpenFOAM-2.3.0/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #1  Foam::sigFpe::sigHandler(int) in "/opt/apps/openfoam-2.3.0/OpenFOAM-2.3.0/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #2
[0]  at sigaction.c:0
[0] #3  Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) in "/opt/apps/openfoam-2.3.0/OpenFOAM-2.3.0/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #4  Foam::sqrt(Foam::tmp<Foam::Field<double> > const&) in "/opt/apps/openfoam-2.3.0/OpenFOAM-2.3.0/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
[0] #5  Foam::compressible::LESModels::vanDriestDelta::calcDelta() in "/home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/lib/libFlameletcompressibleLESModels.so"
[0] #6  Foam::compressible::LESModels::Smagorinsky::correct(Foam::tmp<Foam::GeometricField<Foam::Tensor<double>, Foam::fvPatchField, Foam::volMesh> > const&) in "/home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/lib/libFlameletcompressibleLESModels.so"
[0] #7  Foam::compressible::LESModel::correct() in "/home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/lib/libFlameletcompressibleLESModels.so"
[0] #8
[0]  in "/home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/bin/flameletFoam"
[0] #9  __libc_start_main in "/lib64/libc.so.6"
[0] #10
[0]  in "/home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/bin/flameletFoam"
[tud0028150:17249] *** Process received signal ***
[tud0028150:17249] Signal: Floating point exception (8)
[tud0028150:17249] Signal code:  (-6)
[tud0028150:17249] Failing at address: 0x4d400004361
[tud0028150:17249] [ 0] /lib64/libc.so.6() [0x304a8326b0]
[tud0028150:17249] [ 1] /lib64/libc.so.6(gsignal+0x35) [0x304a832635]
[tud0028150:17249] [ 2] /lib64/libc.so.6() [0x304a8326b0]
[tud0028150:17249] [ 3] /opt/apps/openfoam-2.3.0/OpenFOAM-2.3.0/platforms/linux64GccDPOpt/lib/libOpenFOAM.so(_ZN4Foam4sqrtERNS_5FieldIdEERKNS_5UListIdEE+0x30) [0x7ffd9bad4ec0]
[tud0028150:17249] [ 4] /opt/apps/openfoam-2.3.0/OpenFOAM-2.3.0/platforms/linux64GccDPOpt/lib/libOpenFOAM.so(_ZN4Foam4sqrtERKNS_3tmpINS_5FieldIdEEEE+0x81) [0x7ffd9badf541]
[tud0028150:17249] [ 5] /home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/lib/libFlameletcompressibleLESModels.so(_ZN4Foam12compressible9LESModels14vanDriestDelta9calcDeltaEv+0x3a5) [0x7ffd9f2585d5]
[tud0028150:17249] [ 6] /home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/lib/libFlameletcompressibleLESModels.so(_ZN4Foam12compressible9LESModels11Smagorinsky7correctERKNS_3tmpINS_14GeometricFieldINS_6TensorIdEENS_12fvPatchFieldENS_7volMeshEEEEE+0x23) [0x7ffd9f21bd43]
[tud0028150:17249] [ 7] /home6695/likun/OpenFOAM/likun-2.3.0/platforms/linux64GccDPOpt/lib/libFlameletcompressibleLESModels.so(_ZN4Foam12compressible8LESModel7correctEv+0x35) [0x7ffd9f1a7e65]
[tud0028150:17249] [ 8] flameletFoam() [0x42041d]
[tud0028150:17249] [ 9] /lib64/libc.so.6(__libc_start_main+0xfd) [0x304a81ed5d]
[tud0028150:17249] [10] flameletFoam() [0x41e299]
[tud0028150:17249] *** End of error message *** 


I still don't know what is the problem. Do you have any idea on what could be the possible reason?

Best
Likun

[babakflame]

Dear Likun

I am still trying to validate the LES results of the same code in DOWNSTREAM locations (Upstream good).

For your problem, I GUESS maybe the definition of Compressible LES models has changed from O.F. 2.1.0 to O.F. 2.3.0.

My proposal is using oneEqEddy LES model and check that whether the same problem happens or not.

Best,

Bobi

[Likun]

Dear Bobi,

Thank you for your fast reply.

Indeed, the definitions of compressible LES models has changed from OF2.1. to OF2.3, for examples,

1) the 'LESModel::correct()'

In OF2.1:

void LESModel::correct(const tmp<volTensorField>&)
{
    delta_().correct();
}

In OF2.3 it is:

void LESModel::correct(const tmp<volTensorField>&)
{
    turbulenceModel::correct();
    delta_().correct();
}

2) the 'alphaEff()'

in OF2.1 is:

        //- Return the effective thermal diffusivity
        virtual tmp<volScalarField> alphaEff() const
        {
            return tmp<volScalarField>
            (
                new volScalarField("alphaEff", alphaSgs() + alpha())
            );
        }

in OF2.3 it is:

        //- Return the effective thermal diffusivity
        virtual tmp<volScalarField> alphaEff() const
        {
            return thermo().alphaEff(alphaSgs());
        }

3) the SGS kinetic energy in Smagrinsky model

in OF2.1 is:

        //- Return SGS kinetic energy
        //  calculated from the given velocity gradient
        tmp<volScalarField> k(const tmp<volTensorField>& gradU) const
        {
            return (2.0*ck_/ce_)*sqr(delta())*magSqr(dev(symm(gradU)));
        }

in OF2.3 it is:

        //- Return SGS kinetic energy
        //  calculated from the given velocity gradient
        tmp<volScalarField> k(const tmp<volTensorField>& gradU) const
        {
            volSymmTensorField D(symm(gradU));

            volScalarField a(ce_/delta());
            volScalarField b((2.0/3.0)*tr(D));
            volScalarField c(2*ck_*delta()*(dev(D) && D));

            return sqr((-b + sqrt(sqr(b) + 4*a*c))/(2*a));
        }

The problems should be related to these changes, especially the changes in Smagrinsky model. Because as you suggested, when I switched the LES model to oneEqEddy, the code is now running without problem, at least it past the point where it crashes when using Smagrinsky model.

Best,
Likun

[babakflame]

Dear Likun

My suggestion is first check the LES properties file in O.F. 2.3.o to see whether other inputs are needed in your LES properties file or not (for smagorinsky model).

nest step, might be check the code for adding headers that might be needed.

Best,
Bobi

[Likun]

Originally Posted by babakflame

Dear Likun

My suggestion is first check the LES properties file in O.F. 2.3.o to see whether other inputs are needed in your LES properties file or not (for smagorinsky model).

nest step, might be check the code for adding headers that might be needed.

Best,
Bobi

Dear Bobi,

Thank you for your suggestions, I am still working on this problem.

Best,
Likun

[Likun]

Dear FOAMers,

I have made some more modifications for the flameletFoam-2.3.0 solver, now it works for OpenFoam-2.3.x. The previous problem for LES case running is also solved, but there still no guarantee for free of problem. Feel free to check it: https://sourceforge.net/projects/flameletfoam230/files/.

Best,
Likun

[Likun]

Dear Foamers,

Hagen has created a repository for the flameletFoam code, both the flameletFoam-2.1 and flameletFoam-2.3 are uploaded there. To avoid possible confusion, I have removed the flameletFoam-2.3 code that I have previously uploaded to the sourceforge. The code can now be found here: https://github.com/flameletFoam.

Best,
Likun

[wenxu]

Dear Likun,

Are you using the flameletFoam for further research? Now i am trying this solver but i encounter the following problem:

• I need to generate a flamelet library myself using cantera, but i can not find what the mixture fraction definition is based on? Is it based on the one-step reaction or Bilger's definition which is based on element?

best regards,
wenxu

[Likun]

Dear Wenxu,

I am not using Cantera for generating flamelet library. So I don't know what is the definition of mixture fraction in Cantera.

Best,
Likun

[Hagen]

Dear Wenxu,

the mixture fraction is calculated using a small amount of Argon that is added at the Fuel inlet.

Hagen

[Howard]

Originally Posted by wenxu

Dear Likun,


Are you using the flameletFoam for further research? Now i am trying this solver but i encounter the following problem:

• I need to generate a flamelet library myself using cantera, but i can not find what the mixture fraction definition is based on? Is it based on the one-step reaction or Bilger's definition which is based on element?

best regards,
wenxu

Hi, I'm a new user here. Could I ask after downloading your package how to use it? And I would like to ask if this flameletFoam can be used for premixed combustion.

[Hagen]

Dear Howard,

there is a small description how the code can be used on the extend bazaar in the OpenFoam wiki:
https://openfoamwiki.net/index.php/E...n/flameletFoam

For premixed combustion you will probably need to modify the code, adding a reaction progress-variable, basically switching to FGM. The preprocessing (table generation etc) is different for premixed flames.

Hagen

[Likun]

Originally Posted by Howard

Hi, I'm a new user here. Could I ask after downloading your package how to use it? And I would like to ask if this flameletFoam can be used for premixed combustion.

Hi Howard,

I fully agree with what Hagen said. Flamelet model by concept is for modeling of non-premixed combustion. For premixed combustion you need progress variable as the independent variable instead of mixture fraction as in flamelet model. However, for partially-premixed flame you still need mixture fraction. I think the best way for you is to modify this code, add progress variable. This should not be too difficult if you understand the structure of flameletFoam. I have already implemented FGM model based on the flameletFoam, and it is working fine. After adding progress variable, you need generate a lookup table using progress variable (and mixture fraction) as independent variable. This can be done by Cantera, FlameMaster or CHEM1D. I am using CHEM1D flame Eindhoven university.

Good Luck!

Best,
Likun

[Howard]

Originally Posted by Likun

Hi Howard,

I fully agree with what Hagen said. Flamelet model by concept is for modeling of non-premixed combustion. For premixed combustion you need progress variable as the independent variable instead of mixture fraction as in flamelet model. However, for partially-premixed flame you still need mixture fraction. I think the best way for you is to modify this code, add progress variable. This should not be too difficult if you understand the structure of flameletFoam. I have already implemented FGM model based on the flameletFoam, and it is working fine. After adding progress variable, you need generate a lookup table using progress variable (and mixture fraction) as independent variable. This can be done by Cantera, FlameMaster or CHEM1D. I am using CHEM1D flame Eindhoven university.

Good Luck!

Best,
Likun

Thank you very much for your reply! I think FGM is suitable for my situation. However, since I am only a new user of OpenFoam, what you mentioned is relatively difficult for me. Could you give me some suggestions?

[Likun]

Originally Posted by Howard

Thank you very much for your reply! I think FGM is suitable for my situation. However, since I am only a new user of OpenFoam, what you mentioned is relatively difficult for me. Could you give me some suggestions?

I would suggest to first run some cases with the flameletFoam (for premixed flame), and get familiar with how the flamelet model works. After that you can think of adding a extra transport equation for progress variable. FGM and flamelet model work in very similar ways. But you may also think of using other combustion models (e.g. EDC model) or other solvers, e.g. reactingFoam, they are not restricted to non-premixed combustion, and should suitable for your case. For the EDC model, if you search on the forum, you will find some useful information, for example this one http://www.cfd-online.com/Forums/ope...implefoam.html.

Best,
Likun

[Uyan]

Hagen,

Here you have said the mixture fraction is calculated using a small amount of Argon added from the fuel inlet.

I just wanted to know if my understanding is correct.

Is it added as a tracer element so within the counter-flow flame thickness instead of calculating mixture fraction explicitly by Bilger's formulation, Yar/Yar_fuel is used as the mixture fraction ?

[wenxu]

The definition of mixture fraction based on element can be found here: Masri, A. R., and Bilger, R. W., Comb. Flame 73:261– 285 (1988).

You can also look through this paper, then you will have a clear understanding of mixture fraction: A Consistent Flamelet Formulation for Non-Premixed Combustion Considering Differential Diffusion Effects

regards,
wen