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chtMultiRegionFoam heat transfer issue

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Old   October 23, 2018, 09:04
Unhappy chtMultiRegionFoam heat transfer issue
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Arthur
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Hi,


I am new to OpenFOAM and I am trying to model a conjugate heat transfer model of a solid block being heated through conduction from the bottom surface and being cooled by a flowing 'block' of fluid flowing over the top surface. So far I have the solid block conducting completely fine, however the fluid block is not heating or cooling (or interacting with) the top surface of the block at all.


Could this issue be because of the way that the interface is defined? I have included the code for the 0/T file for the solid below (the formatting issue is only from when i copy/pasted it onto the website). *I can supply any additional code if required.*
Any help would be greatly appreciated!

Thank you!


FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0/solid";
object T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [ 0 0 0 1 0 0 0 ];

internalField uniform 300;

boundaryField
{
#includeEtc "caseDicts/setConstraintTypes"

heater
{
type fixedValue;
value 500;
}

"solid(solidToFluid|Base)"
{
type zeroGradient;
}
solid_to_fluid
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
value $internalField;
Tnbr T;
kappaMethod solidThermo;
}
}

Last edited by amdk136; October 23, 2018 at 09:07. Reason: additional info
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Old   October 23, 2018, 09:39
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Peter Hess
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Hello,

Which Version of OF are you using?

If OF6 then be sure that you are simulating steady state.

Check up the ddt sheme (in the solid and fluid), if euler or steasy state.

If you are simulating transient, a solution will be reached. But you need to simulate long.

Turn the simulation to steady state or increase the time steps.

------

If the version is OF5 older than 6 then the simulation is transient and you should use: chtMultiRegionSimpleFoam

------

You dont talk about any deconvergence or crashing, that means at least the simulation runs ad produce results...

Or you are making a post processing mistake.

After running the simulation type:

paraFoam -touchAll

paraFoam -region "your fluid region"

Like that you use the fluid results alone.

Be sure the time is the last one in paraFoam.

Print temperature.

What do you see?

------

Print a shot of a time step from the log file please.


Regards

Peter
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Last edited by peterhess; October 26, 2018 at 07:20.
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Old   October 23, 2018, 10:02
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Arthur
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Quote:
Originally Posted by peterhess View Post
Hello,

Which Version of OF are you using?

If OF6 then be sure that you are simulating steady state.

Check up the ddt sheme (in the solid and fluid), if euler or steasy state.

If you are simulating transient, a solution will be reached. But you need to simulate long.

Turn the simulation to steady state or increase the time steps.

------

If the version og OFis older than 6 then the simulation is transient and you should use: chtMultiRegionSimpleFoam

------

You dont talk about any deconvergence or crashing, that means at least the simulation runs ad produce results...

Or you are making a post processing mistake.

After running the simulation type:

paraFoam -touchAll

paraFoam -region "your fluid region"

Like that you upload the fluid results alone.

Be sure the time is the last one in paraFoam.

Print temperature.

What do you see?

------

Print a shot of a time step from the log file please.


Regards

Peter

Peter,


OpenFOAM 6 is being used.


The simulation runs fine and the tempoerature of the solid block on the bottom changes correctly. When running "paraFoam -region -fluid" it shows a 0.05K increase.



As you have asked for, here is the time step from the log file:
Code:
Solving for fluid region fluid
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 7.07547e-11, Final residual = 7.07547e-11, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 2.28422e-09, Final residual = 2.28422e-09, No Iterations 0
DILUPBiCGStab:  Solving for Uz, Initial residual = 1.17482e-09, Final residual = 1.17482e-09, No Iterations 0
DILUPBiCGStab:  Solving for h, Initial residual = 9.78777e-06, Final residual = 6.28479e-09, No Iterations 1
Min/max T:300 420.101
GAMG:  Solving for p_rgh, Initial residual = 6.15382e-08, Final residual = 6.15382e-08, No Iterations 0
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 2.02462e-13, global = 3.82798e-15, cumulative = 3.82798e-15
Min/max rho:1.225 1.225

Solving for solid region solid
GAMG:  Solving for h, Initial residual = 0.000433589, Final residual = 3.47651e-16, No Iterations 1
Min/max T:400.094 1000
ExecutionTime = 272.54 s  ClockTime = 288 s

Region: fluid Courant Number mean: 0.197803 max: 0.998812
Region: solid Diffusion Number mean: 0.000329392 max: 0.0235509
deltaT = 0.00194175
Time = 4.8932

Would I be correct in saying that from the log it appears that the fluid is heating up and that ParaView is just not showing the heating up?


I have also set it to run for a larger time.
Thank you for your help.


Regards,
Arthur
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Old   October 23, 2018, 10:21
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Peter Hess
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Quote:
Originally Posted by amdk136 View Post
Peter,


OpenFOAM 6 is being used.


The simulation runs fine and the tempoerature of the solid block on the bottom changes correctly. When running "paraFoam -region -fluid" it shows a 0.05K increase.



As you have asked for, here is the time step from the log file:
Code:
Solving for fluid region fluid
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 7.07547e-11, Final residual = 7.07547e-11, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 2.28422e-09, Final residual = 2.28422e-09, No Iterations 0
DILUPBiCGStab:  Solving for Uz, Initial residual = 1.17482e-09, Final residual = 1.17482e-09, No Iterations 0
DILUPBiCGStab:  Solving for h, Initial residual = 9.78777e-06, Final residual = 6.28479e-09, No Iterations 1
Min/max T:300 420.101
GAMG:  Solving for p_rgh, Initial residual = 6.15382e-08, Final residual = 6.15382e-08, No Iterations 0
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 2.02462e-13, global = 3.82798e-15, cumulative = 3.82798e-15
Min/max rho:1.225 1.225

Solving for solid region solid
GAMG:  Solving for h, Initial residual = 0.000433589, Final residual = 3.47651e-16, No Iterations 1
Min/max T:400.094 1000
ExecutionTime = 272.54 s  ClockTime = 288 s

Region: fluid Courant Number mean: 0.197803 max: 0.998812
Region: solid Diffusion Number mean: 0.000329392 max: 0.0235509
deltaT = 0.00194175
Time = 4.8932

Would I be correct in saying that from the log it appears that the fluid is heating up and that ParaView is just not showing the heating up?
Well, from the log file, the temperature of the fluid is 420.

The temperature of the fluid is increasing...

I would say you still have a postprocessing problem...

Are you simulating steady state?

Regards

Peter
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Old   October 23, 2018, 10:46
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Arthur
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Quote:
Originally Posted by peterhess View Post
Well, from the log file, the temperature of the fluid is 420.

The temperature of the fluid is increasing...

I would say you still have a postprocessing problem...

Are you simulating steady state?

Regards

Peter

Peter,


Thank you for your confirmation about the log file.


I will take it on board that it is a post-processing problem and try and figure that out!


I am simulating transient conditions, and am using chtMultiRegionFoam in OpenFOAM 6.


Thank you again for your help, it is much appreciated!!

Regards,

Arthur
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