[CHUMMAR]

I have created a rectangular enclosure with the left portion as solid and right portion as fluid since I am working on a problem related to conjugate heat transfer (chtMultiRegionFoam) . I have to give a hot wall side condition of 360K which is the left side wall of the solid region. Is this possible to be added in the '0/solid/T' file OR do I have to consider the left wall as a heater and give it separate boundary conditions.

I just started working on OpenFOAM and so pls forgive any mistakes i have done in code. (RED -FLUID BLUE -SOLID)

CODE:
dimensions [ 0 0 0 1 0 0 0 ];

internalField uniform 360;

boundaryField
{

inlet
{
type patch;
}

frontAndBack
{
type zeroGradient;
}

topAndBottom
{
type zeroGradient;
}

solid_to_fluid
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
value $internalField;
Tnbr T;
kappaMethod solidThermo;
}
}

THANKYOU

[Yann]

Hi Amal,

If you need to specify a fixed temperature on the left wall of your solid, you need to use a fixedValue boundary condition for this wall in the file 0/solid/T.

From your post this is hard to tell but if the frontAndBack and topAndBottom boundaries are named properly, I guess the inlet boundary must be your left wall, right?

If this is right, then you have to set a fixedValue boundary condition on "inlet".

Cheers,
Yann

[CHUMMAR]

Yes, as you presumed sir.....my inlet was the left side wall with rest of them being adiabatic walls. I gave 365K as a fixed value as such. I also gave a fixed value of 300K at the outlet.

This is the code I used :

Inlet file in : 0/solid/T

dimensions [ 0 0 0 1 0 0 0 ];

boundaryField
{

inlet
{
type fixedValue;
value (365 0 0);
}

frontAndBack
{
type zeroGradient;
}

topAndBottom
{
type zeroGradient;
}

solid_to_fluid
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
value $internalField;
Tnbr T;
kappaMethod solidThermo;
}
}

Outlet file in 0/fluid/T :

dimensions [ 0 0 0 1 0 0 0 ];

boundaryField
{

outlet
{
type fixedValue;
value (300 0 0);
}

frontAndBack
{
type zeroGradient;
}

topAndBottom
{
type zeroGradient;
}

fluid_to_solid
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
value $internalField;
Tnbr T;
kappaMethod fluidThermo;
}
}

-----------------------------------------------------------------------

After giving the parafoam command I am not able to select T and see the isotherms. If I click celltoregions this is the picture I get(attached). I am actually trying to give to Temperature conditions on the inlet and outlet and obtain isothermal contours as shown in the attached file.

[Yann]

You will have to give more information in order to get some help.
Did the solver run properly? Do you have a log file?

How are you opening paraView? With paraFoam? Have you reconstructed your case before starting paraView?

In order to visualize your results in paraView, just load "fluid/internalMesh" in the "Mesh Parts" section. Then at the top of the window, in the "Time" selector, go to the latest time to be able to visualize the final result of your simulation.

From your screenshot it seems you don't have any timeStep written except "0", so it seems something is wrong.

Yann

[CHUMMAR]

I have attached a picture of the way i execute the chtmultiregion command in the terminal and also have attached the log files as requested.(ZIP FILE)



Thank you a lot Sir for the help

[Yann]

When you run a case, it is important to have a look at the log files to check if everything went as expected.

In your case, you have an error on the decomposePar step:

--> FOAM FATAL IO ERROR: 
 keyword n is undefined in dictionary "/home/chummarvm/OpenFOAM-dev/tutorials/heatTransfer/chtMultiRegionFoam/newtest/system/fluid/decomposeParDict"

Check the file system/fluid/decomposeParDict: it must exist and be properly defined.

You don't see any result because your solver did not run and hence did not write any data. You have to fix the decomposePar first and then see if it solves your problem or if another error arises.

Cheers,
Yann

[CHUMMAR]

I have 3 decompose ParDict files.......


One in solid, fluid and one in the system folder.


I have copied them from another chtmultiregion case without knowing the syntax



Since i am a newbie i did so as seen in tutorials.......
--------------------------------------------------------------------------------------------------------------------

CODE:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
note "mesh decomposition control dictionary";
location "system";
object decomposeParDict;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

numberOfSubdomains 8;

method simple;

hierarchicalCoeffs
{
n (4 1 2);
delta 0.001;
order xyz;
}
-----------------------------------------------------------------------------------------


This is what I have pasted in all 3 files......to get the outputs of T, U and also isotherm plots how should i change this file



Thanks in advance
CHUMMAR

[Yann]

Hi,

I think your problem might come from the decomposeParDict definition. You use the "simple" method, but the coefficients are defined as "hierarchicalCoeffs" instead of "simpleCoeffs".

Try updating your decomposeParDict files with either this:

numberOfSubdomains 8;

method hierarchical;

hierarchicalCoeffs
    {
        n        (4 1 2);
        delta    0.001;
        order    xyz;
    }

Or this:

numberOfSubdomains 8;

method simple;

simpleCoeffs
    {
        n        (4 1 2);
        delta    0.001;
      }

Let us know if decomposePar works fine after this.



Yann

[CHUMMAR]

I corrected the decompose Par file as u have suggested Mr.Yann


It ran without any errors and i obtained 8 processor files from 0 to 7. (Progress )



But the problem i still have is I cannot view the Temperature plot or isotherms in the post processing.


I have attached the decompose Par file to this reply


The plot which I am trying to obtain is also attached to this mail.....

[Yann]

OK so now we have solved the decomposeParDict issue, we can move to the next step.

Do not try to rush into visualizing your results if you did not check what happened during the previous steps.

The log you posted shows this:

--> FOAM FATAL IO ERROR: 
Illegal dictionary entry or environment variable name "internalField"
Valid dictionary entries are 1(type)

file: /home/chummarvm/OpenFOAM-dev/tutorials/heatTransfer/chtMultiRegionFoam/newtest/0/fluid/T.boundaryField.fluid_to_solid from line 41 to line 41.

As long as you get Fatal errors, you will not be able to properly run your simulation. Now you have to solve this issue before moving forward.

Yann

[CHUMMAR]

dimensions [ 0 0 0 1 0 0 0 ];

boundaryField
{

outlet
{
type fixedValue;
value (300 0 0);
}

frontAndBack
{
type zeroGradient;
}

topAndBottom
{
type zeroGradient;
}

fluid_to_solid
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
value $internalField;
Tnbr T;
kappaMethod fluidThermo;
}
}
----------------------------------------------------------------------------------------------------


This is the syntax i was shown for region interface while going through vidz

[Yann]

Can you post the whole file please ?

[CHUMMAR]

I have attached the 0/fluid/ files such as T U n all ]


THANKS,
CHUMMAR

[Yann]

There is one line missing in your T file to initialize the internalField:

dimensions      [0 0 0 1 0 0 0];

internalField   uniform 293;//set the initial temperature of your domain here

boundaryField
{
    ...
}

There is also an error in the outlet boundary condition. You set a vector, but temperature is a scalar so you will also get an error. Here is the proper syntax:

    outlet
    {
        type            fixedValue;
        value           uniform 300;
    }

[CHUMMAR]

Thanks a lot for your valuable suggestions Sir,


I am still not able to obtain temperature contours on paraview.....not able to select T n view


I have attached the new set of log files.....


Also i started getting an error message for DecomposePar file......but not during the execution but as i was viewing within paraview........Does this have to do with the execution?

[Yann]

Hi Amal,


Look at your decomposePar log, you still have an error there.



Consequently, chtMultiRegionFoam did not run. It is useless to try visualizing your results as long as your solver did not run.



Yann

[CHUMMAR]

I corrected the errors in the corresponding decomposePar file Yann Sir.

Now it is not showing any fatal errors but showing field transfer from processor 0 to 7.


Still not getting any isotherm plots in paraview though

[CHUMMAR]

Forgot to attach the new decomposePar file with previous reply Sir.

[Yann]

Great!


Then move on to the next steps and check the log files to see if there is any error or if your solver runs properly.

[CHUMMAR]

I am new to openfoam CFD.... I have to input continuity, momentum and energy equations into a geometrical problem containing heat transfer and obtain temperature plots. How is this possible?