Volume fraction calculation in EDEM-Fluent coupling.

fyw
fyw Altair Community Member
in Community Q&A

Hello,
I want to simulate flow impingement of a particle bed. The problem is that the mesh requirement in the center area of ​​the nozzle conflicts with the requirement that the mesh size need to be larger than the particle size.


For example, a nozzle diameter of 6mm requires a mesh size of 1mm. A particle size of 2mm requires a mesh size of 5mm.


Using a mesh of 1mm results in floating point exception errors, which are caused by an error in the volume fraction calculation. The image below shows the problem. The left part is the nozzle and the right area is filled with particles. You can see that the volume fraction deviates in the middle of the right area, where the mesh size is 1mm.

54a371e80d1d3edf17bf1a750a90607.png

And using a mesh of 6mm results in flow convergence errors.

My opinion on this problem is that I need to improve the ddpm method. For example, divide the large particles into 27 pieces when calculating the volume fraction. I would like to know how to modify the EDEM-Fluent coupling code. And is there any other way to solve this problem?

fang yanwei

24.11.16

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Answers

  • Stephen Cole
    Stephen Cole
    Altair Employee

    Hi Fang,

    You could introduce the particles after the nozzle so they are only in the larger mesh area. Or consider using EDEM-AcuSolve coupling where the mesh size limitations are resolved:

    https://learn.altair.com/course/view.php?id=176

    Modifying the Fluent coupling code is possible but would be challenging, on the EDEM Coupling Interface you can find the documentation here:

    https://help.altair.com/edem/topics/coupling_interface_programming_guide/introducing_the_coupling_interface_programming_guide_c.htm

    You would also have to check the Fluent documentation for modification of the models on the Fluent side.


    Regards

    Stephen

  • fyw
    fyw Altair Community Member
    edited November 20

    Hi Stephen,

    I checked the coupling code. There are two kinds of coupling code, one base on Eulerian source term and one based on DPM.

    Volume fraction refinement is relised in the first one, which used sample points generated by EDEM.

    The second one inject particle into Fluent and volume fraction calculation is done by Fluent.

    So it seems resonable to use the first code to do large particle simulation, but I find it is unstable when calculating the packed bed case in e-learning. The second one works well in this case.

    Thus, there's a contradiction in the choice of couplling code. I finally choose to use the second code with a coarser mesh to simulation the impingement case.

    Is there any other suggestions?

    Thank you very much for relpying! It helps a lot!

    fang yanwei

    2024.11.20

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