[sandymech]

Hi to All OpenFoam Users,
I am new to OpenFoam. I am trying to setup case where it involves conjugate heat transfer with volumetric heat generation in solid cylinder and heat is exchanged with fluid through natural convection. I have already set up case and you can find in given tar file.

The problem is centreline of solid cylinder always shows minimum temperature as compared to domain. Result file picture is shown in attached picture. I am not sure, where I am going wrong. You all are kindly requested to help me in this regard.

Thanks in advance!

[stubbs]

Hello,

I am also new to OpenFOAM. Your case is interesting to me, and I would like to duplicate it on my own system for analysis. However, I am unable to successfully execute the case as is. Possibly, I am making some mistake, but I wonder if the issue could be due to differing versions of OpenFOAM. Can you please provide your OpenFOAM version as well as what post-processor you are using and its version?

Thank you.

[sandymech1]

Hi Andrew,

Openfoam version - 4.1
Paraview - 5.4.1

If you can send me error message, I can help you out.

If you are using Openfoam 5.0 then you may have to change in fvOptions file for Tmin and Tmax , you may have to write min and max respectively.

Thanks,
Sandeep

[stubbs]

Sandeep,

Thank you for the reply. I am using OpenFOAM 2.4 - perhaps I need to upgrade....

I have actually encountered a couple of errors already, the first having to do with decomposing and reconstructing the case. I only have 2 processors, so I modified the appropriate lines in the deconstructPar files. My system seems to be decomposing the case correctly between the 2 processors, but I get the following error in log.reconstructPar:

Code:

--> FOAM FATAL ERROR:
No times selected

From function reconstructPar
in file reconstructPar.C at line 210.

FOAM exiting

I also get the following error in log.chtMultiRegionSimpleFoam:

Code:

--> FOAM FATAL IO ERROR:
keyword kappa is undefined in dictionary "/home/amiadmin/OpenFOAM/amiadmin-2.4.0/run/examples/cylnatural_send/0/fluid/T.boundaryField.fluid_to_solid"

file: /home/amiadmin/OpenFOAM/amiadmin-2.4.0/run/examples/cylnatural_send/0/fluid/T.boundaryField.fluid_to_solid from line 51 to line 55.

From function dictionary::lookupEntry(const word&, bool, bool) const
in file db/dictionary/dictionary.C at line 442.

FOAM exiting

Again, I am new to OpenFOAM, so I am not really sure what to change here. The extent of my experience is running through a couple of the step-by-step tutorials.

Thanks,
Andrew

[sandymech1]

Try to upgrade OPENFOAM4.0 and let me know if there is any problem.

[stubbs]

Hi Sandeep,

I have upgraded to OpenFOAM 4.1, and Paraview 5.0.1. I am also using a different machine now that has 4 processors, so I have not made any changes to your original case files. Now when I run the case, I am getting the following errors:

Error in log.changeDictionary.fluid:
Code:

Writing modified fieldDict U
Replacing entries in dictionary epsilon
Loading dictionary epsilon


--> FOAM FATAL IO ERROR:
cannot find file

file: /home/andrew/OpenFOAM/andrew-4.1/run/CFD-Online/cylnatural_send/0/fluid/epsilon at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 72.

FOAM exiting

Error in log.reconstructPar:
Code:

Create time



--> FOAM FATAL ERROR:
No times selected

From function int main(int, char**)
in file reconstructPar.C at line 225.

FOAM exiting

The chtMultiRegionSimpleFoam solver appears to be executing OK. At least there are no errors in the log file anymore, and I have data for timesteps 0, 10, 20, ... , 100.

When I attempt to open "cylnatural_send.OpenFOAM" in Paraview, I can't see any data, and I get the following error messages:
Code:

ERROR: In /home/ubuntu/OpenFOAM/OpenFOAM-4.1/applications/utilities/postProcessing/graphics/PVReaders/PVFoamReader/PVFoamReader/vtkPVFoamReader.cxx, line 216
vtkPVFoamReader (0x3b304a0): could not find valid OpenFOAM mesh


ERROR: In /home/openfoam/OpenFOAM/ParaView-5.0.1/VTK/Common/ExecutionModel/vtkExecutive.cxx, line 784
vtkPVCompositeDataPipeline (0x3b20950): Algorithm vtkPVFoamReader(0x3b304a0) returned failure for request: vtkInformation (0x3b0c270)
Debug: Off
Modified Time: 162047
Reference Count: 1
Registered Events: (none)
Request: REQUEST_INFORMATION
ALGORITHM_AFTER_FORWARD: 1
FORWARD_DIRECTION: 0

Opening "cylnatural_send{fluid}.OpenFOAM" in Paraview lets me see the fluid data, but still gives the following error messages:
Code:

ERROR: In /home/ubuntu/OpenFOAM/OpenFOAM-4.1/applications/utilities/postProcessing/graphics/PVReaders/PVFoamReader/PVFoamReader/vtkPVFoamReader.cxx, line 289
vtkPVFoamReader (0x464b100): Reader failed - perhaps no mesh?


ERROR: In /home/openfoam/OpenFOAM/ParaView-5.0.1/VTK/Common/ExecutionModel/vtkExecutive.cxx, line 784
vtkPVCompositeDataPipeline (0x46618b0): Algorithm vtkPVFoamReader(0x464b100) returned failure for request: vtkInformation (0x4beeee0)
Debug: Off
Modified Time: 197831
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FORWARD_DIRECTION: 0
FROM_OUTPUT_PORT: 0
ALGORITHM_AFTER_FORWARD: 1

Finally, opening "cylnatural_send{solid}.OpenFOAM" in Paraview lets me see the solid data, and it does not produce any error message.

My end result in Paraview looks very similar to the original picture you posted - maximum temp is on the outside of the cylinder and the center of the cylinder has minimum temperature of 300K. There is one notable exception though - the maximum temperature is only 302K instead of 556K as shown in your picture.

Any advice you can offer on what is going wrong would be greatly appreciated.

Thanks,
Andrew

[agustinvo]

Hi. I saw in your 0/solid/T:

dimensions      [ 0 0 0 1 0 0 0 ];

internalField   uniform 300;

boundaryField
{
     solid_to_fluid
    {
         type            compressible::turbulentTemperatureCoupledBaffleMixed;
        value           uniform 300;
        kappaMethod     solidThermo;
        kappaName       none;
        Tnbr            T;
}
}

Why don't you try to initialize with your expected reached temperature? Which solver are you using? Do you assume a heat source, or just a fixed temeprature in your solid?

[sandymech1]

Hi Andrew,

To reach 500K or more temperature, you may have run the case for end time like 2000.

For error in changedictionary file, you may have to copy epsilon and k file from any other case file to 0/fluid

e.g. Assuming working directory is case directory, you can use following commands
cp ../heatExchanger/0.orig/air/k 0/fluid/
cp ../heatExchanger/0.orig/air/epsilon 0/fluid/

Thanks,
Sandeep

[Bloerb]

I have not tested it, but this seems mesh related. Try changing your cylinder mesh from a wedge type at the center to something else.

[Cagatayemre]

Hello Sandy, I am a graduate student and I need to solve a similar problem by using openFOAM as my computational methods class project. Is it possible to solve this problem unsteady by using chtMultiRegionSimpleFoam. I want to solve it unsteady because I need to validate the results with results in the literature. Results in the litearature are unsteady. Or do you have any steady results. I need to compare my results with them. Thank you very much.