Learning Forum

[Akuruwa]

Hello,

I am working on 2D simulation of nanoparticle agglomerates in bubbling fluidised bed using Fluent. I want the gas phase to be continuous/eulerian and solid phase to be discrete/lagrangian. I am facing multiple difficulties with respect to the definition of the discrete phase i.e. solids.

1. When selecting discrete phase based modelling, it asks me to define injection. In the experiments I am initially filling it up with solid. However when defining injection, I was not able to make a fixed bed that would later be fluidised. In Eulerian simulation, the patch function worked for initialisation, but how can I make fluidised bed work for Discrete/Lagrangian solid type of simulation?
2. Since I am simulating nanoparticles, I want to define the proper cohesion/ particle interaction properties. Is it possible to do so in ANSYS 19.2 or later versions? Or is it necessary to combine with Rocky for simulations?

Thanks,

Anuj Kuruwa

[ai0013]

1) Perhaps take a look at "file" injection. This type of injection tells Fluent (among other particle properties) to read x, y and z positions from an external file. There is specific format to do this.so better refer to the manual. A turn around could be to: during the mesh generation process, split your mesh into two fluid regions, one of course delimited by the initial height of the bed, while the other is simply the rest of your cells. This way Fluent can later recognize them as individual fluid regions. You can then use surface injection and choose the int_fluid region of interest. Particles will be injected from the interior faces of the cells defined by this region, as if they "sprout" from the mesh itself.
2) I am not sure about cohseive forces, but particle-particle interaction can be accounted by the DEM model.

[Rob]

To add, the DEM model tends to become quite expensive due to the collision overlap terms, so for a fluidised bed I'd always use the Eulerian-granular model.