Chip cooling ==> new solver available

[thschrader]

There is a new solver for using with the cfdof-wb GUI: buoyantSimpleFoam
https://github.com/jaheyns/CfdOF

I ran a simple test-case, chip-cooling.

chipCooling.FCStd

(20.94 KiB) Downloaded 185 times

Dependency-checks ok.
During calculation, only the k/omega residuals are plotted.
I have no experience with buoyantSimpleFoam, comments welcome.
My openfoam version: bluecfd-core 2017-2
Freecad:
OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.21937 (Git)
Build type: Release
Branch: master
Hash: 0de5a290113800dc5779a76d7e216bd882e0ed1e
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Germany (de_DE)

chip_cooling-test.JPG (20.09 KiB) Viewed 6871 times

[oliveroxtoby]

There is a new solver for using with the cfdof-wb GUI: buoyantSimpleFoam
https://github.com/jaheyns/CfdOF

I ran a simple test-case, chip-cooling.
chipCooling.FCStd


Dependency-checks ok.
During calculation, only the k/omega residuals are plotted.
I have no experience with buoyantSimpleFoam, comments welcome.
My openfoam version: bluecfd-core 2017-2
Freecad:
OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.21937 (Git)
Build type: Release
Branch: master
Hash: 0de5a290113800dc5779a76d7e216bd882e0ed1e
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Germany (de_DE)
chip_cooling-test.JPG

Thanks for testing! The residual issue should be resolved.

[Greg66]

Hi,
i did some testing with this new solver.

I used this sample file as a basis.

There are problems with BC "constant heat flux" where simulation is aborted:

OpenFOAM IO error: wrong token type - expected Scalar, found on line 47 the word 'None' file: C:/Users/
UserName/Documents/FreeCad/Temp/case/0/T.boundaryField.chip.gradient at line 47.
14.9: Simulation exited with error

Reason: gradient of BC "Chip" is set to "none" instead to defined value

[oliveroxtoby]

Hi,
i did some testing with this new solver.

I used this sample file as a basis.

There are problems with BC "constant heat flux" where simulation is aborted:

OpenFOAM IO error: wrong token type - expected Scalar, found on line 47 the word 'None' file: C:/Users/
UserName/Documents/FreeCad/Temp/case/0/T.boundaryField.chip.gradient at line 47.
14.9: Simulation exited with error

Reason: gradient of BC "Chip" is set to "none" instead to defined value

Thank you for reporting. This should be resolved.

[Greg66]

Hi,
i did some testing with this new solver.

I used this sample file as a basis.

There are problems with BC "constant heat flux" where simulation is aborted:

OpenFOAM IO error: wrong token type - expected Scalar, found on line 47 the word 'None' file: C:/Users/
UserName/Documents/FreeCad/Temp/case/0/T.boundaryField.chip.gradient at line 47.
14.9: Simulation exited with error

Reason: gradient of BC "Chip" is set to "none" instead to defined value

Thank you for reporting. This should be resolved.

Upon further testing i discovered another issue with material library.

I want to do a simulation with water as fluid using this solver. The requird properties of water (and other liquids) are not existing in your database. The database seems to be corrupted somehow qas you can see in attached picture. Only data of "Air" are available.

On writing the OF-simulation case the thermophysicalProperties file is always set up as "ideal gas". For liquids like water this is not suitable. I would recommend to utilise a polynomial approach like explained here for water: https://holzmann-cfd.com/community/blog ... ties-water
I used this polynomial approach by replacing the original file and it works quite well.

p.s. I do have a big database with physical properties at hand. This database contains several hundred components and comes from another Open Source project for process simulations. If you want, you can contact me on how to utilise this for your tool. This would be a great new feature!

[oliveroxtoby]

Upon further testing i discovered another issue with material library. :o

I want to do a simulation with water as fluid using this solver. The requird properties of water (and other liquids) are not existing in your database. The database seems to be corrupted somehow qas you can see in attached picture. Only data of "Air" are available.

It's not really corrupted - I just didn't get around to adding the extended properties for anything except air. It shouldn't show them, of course, but you can always enter your own values for the material you are using.

Any contribution by members of the community in adding these values would be very much appreciated. No programming needed.

On writing the OF-simulation case the thermophysicalProperties file is always set up as "ideal gas". For liquids like water this is not suitable. I would recommend to utilise a polynomial approach like explained here for water: https://holzmann-cfd.com/community/blog ... ties-water
I used this polynomial approach by replacing the original file and it works quite well.

p.s. I do have a big database with physical properties at hand. This database contains several hundred components and comes from another Open Source project for process simulations. If you want, you can contact me on how to utilise this for your tool. This would be a great new feature! :P

Those are great suggestions but not something I have time to do myself. Please consider contributing.

Thanks

[thschrader]

...
I just didn't get around to adding the extended properties for anything except air.
...

2 questions:
cfdof uses the materials located in
C:\Users\xyz\AppData\Roaming\FreeCAD\Mod\CfdOF\data\CfdFluidMaterialProperties
right?

For editing new fluids, I must use the air material as reference, right? (I mean the order of the entries..)

fluidProperties.JPG (129.74 KiB) Viewed 6605 times

[Greg66]

Those are great suggestions but not something I have time to do myself. Please consider contributing.

I offer you to prepare a database with these components containing the required parameters!


i checked the suggestion by THSchrader to edit the existing database file for water and to supply some missing parameters for water.
The new parameters are showing up in the dialog now. So far so good.

BUT !!! The actual file is only created for an ideal gas model
-> this means, that you only can simulate gases but no liquids

==>> please consider to create a thermophysicalProperties file as you do now only for gases!!
==>> for liquids you should create this file with a polynomials approach as mentioned earlier.

[oliveroxtoby]

2 questions:
cfdof uses the materials located in
C:\Users\xyz\AppData\Roaming\FreeCAD\Mod\CfdOF\data\CfdFluidMaterialProperties
right?

Yes

For editing new fluids, I must use the air material as reference, right? (I mean the order of the entries..)
fluidProperties.JPG

Yes; the order doesn't matter.

Thanks!

[oliveroxtoby]

Those are great suggestions but not something I have time to do myself. Please consider contributing.

I offer you to prepare a database with these components containing the required parameters!


i checked the suggestion by THSchrader to edit the existing database file for water and to supply some missing parameters for water.
The new parameters are showing up in the dialog now. So far so good.

BUT !!! The actual file is only created for an ideal gas model
-> this means, that you only can simulate gases but no liquids

==>> please consider to create a thermophysicalProperties file as you do now only for gases!!
==>> for liquids you should create this file with a polynomials approach as mentioned earlier.

I fully agree with your suggestions and thank you for the offer. However unfortunately this is not something I personally have time for at the moment, but I will happily review any pull requests containing such enhancements.