Temperature Dependent Properties (Fluid Phase)

Submitted by mardussa on Wed, 08/29/2018 - 07:56

Hi CFDEM users,

I am hoping to implement a model in CFDEM similar to the test case of the packedBedTemp supplied with the code. For those that have not run this case, this case is where there is air flowing through a region of packed particles. The particles are at a higher temperature than the passing fluid, and as such the temperature of the air increases as it passes the pebbles (there is also cooling of the particles, not concerned with this at the moment).

My problem is that I would like to also look at that temperature dependent properties of the air (or other fluid). Initially I want to start tracking how the density of the air changes with its temperature variation. I have seen a post from a couple years ago on these forums stating that this is not a functionality currently implemented in CFDEM, and that there would need to be changes made to the solver for this to work. I am not sure what kind of changes need to be unfortunately.

Does anyone have any experience with this? So far I have only been able to search for information regarding temperature dependent fluid properties when it refers to just OpenFOAM. I assume that the procedure would be quite similar, although I am still not sure how to implement something like an icoPolynomial equation of state for a liquid (or better yet, just implement the Boussinesq approximation).

I will keep trying to get this going, but any suggestions would be greatly appreciated.

Kind regards,
Rob

Forums:

paul | Thu, 08/30/2018 - 18:21

You'd need a compressible solver supporting thermodynamical models in the style of OpenFOAM. CFDEMcoupling-PUBLIC does not contain any.

mardussa | Fri, 08/31/2018 - 02:10

Thank you Paul.
So I would need to adapt one of the OpenFOAM solvers such as rhoPimpleFoam or buoyantPimpleFoam to be a solver in CFDEM in a similar way to how pisoFoam is the basis of the cfdemSolverPiso* solvers?
Also, how can I find out what the functionality of the other forms of CFDEMcoupling are? I could not find on the website anywhere that specifies what is and isn't included.
Regards,
Robert

paul | Fri, 08/31/2018 - 09:42

> So I would need to adapt one of the OpenFOAM solvers such as rhoPimpleFoam or buoyantPimpleFoam to be a solver in CFDEM in a similar way to how pisoFoam is the basis of the cfdemSolverPiso* solvers?

Yes. Also, consider using libCFDEMcomp under $CFDEM_SRC_DIR/lagrangian/cfdemParticleComp (just the regular lib w/ all the density-dependent switched on using preprocessor macros).

> Also, how can I find out what the functionality of the other forms of CFDEMcoupling are? I could not find on the website anywhere that specifies what is and isn't included.

Talking to DCS directly, I guess ;)

mardussa | Mon, 09/03/2018 - 02:09

Thank you Paul. I will start to try and adapt a suitable compressible solver.
I am not sure what you mean by using libCFDEMcomp, as my $CFDEM_SRC_DIR/lagrangian/cfdemParticleComp directory only contains a files and options. Is it a different way of compiling CFDEM in the first place?

I sent a message to DCS through the contact page last week asking about the functionality, so hopefully I will have a reply soon.
Kind regards,
Rob

mardussa | Wed, 09/05/2018 - 02:11

Thank you Daniel. I checked my compilation and the preprocessor flag is set in the Options file as it is on github (ie PFLAGS+= -Dcompre). Does this mean that the compressible library is enabled? Although I am not sure what is meant by it enabling different code paths.

I also spoke with my supervisor, and he said that in my case (for adding temperature dependent properties such as density and others) that I should be able to add the temp. dependent density into an incompressible solver as long as it is accounted for in the pEqn such that the mass in the system is conserved. My flows are well below Mach 0.3 so compressible solver may not be necessary? If anyone has any thoughts let me know please.

Kind regards,
Robert

mardussa | Tue, 09/11/2018 - 08:26

I have done some more looking around and reading and after looking at another post the Paul has replied too concerning setting compressible libraries I believe I have now correctly compiled CFDEM with the compressible libraries.

I am not quite sure what is different in between the incompressible compilation and the compressible compilation. You have mentioned they use the same files (as in the same src files?) as each other. If this is the case, how does including the preprocessor flag PFLAG+= -Dcompre turn on the inclusion of density-dependence in the library. Could someone suggest where I can look at the difference between the incompressible and compressible libraries.

Thank you in advance,
Robert

Daniel Queteschiner | Tue, 09/11/2018 - 17:06

Just search the source files for #ifdef compre. This is a compile-time switch. Depending on whether compre is defined or not, different parts of the code are enable/disabled.