[rahulksoni]

We are conducting hydrocyclone simulations through CFD-DEM coupled modeling using OpenFoam and LIGGGHTS. The hydrocyclone is illustrated in the attached snapshot. We employ coal particles of varying sizes, such as -2+1.4, -1.4+1.18, -1.18+1.0, and -1.0+0.6 mm, with distinct densities. The primary forces considered are the drag force, pressure gradient force, viscous force, and surface tension.

It is a multiphase simulation (air and water as fluid and particle as dispersed solid phase). We have tried different drag models, but among them, the Koch-Hill drag model seems to yield favorable accuracy. Additional forces, such as Archimedes' force and virtual mass force, were also accounted for in a few simulations, but the results deviated significantly from expectations. We have attempted various turbulence models as well, but the simulation always seems to stop after a certain duration. For example, with LES model simulation runs for 3.8 seconds. Another challenge we face is the lack of a suitable air core inside the hydrocyclone during simulation.

Tried with different boundary conditions as well. I attempted initialing the simulation with different volume fractions of air and water, but the run failed after some time. Often, the backflow (inside) of air through the spigot (bottom outlet) is not sustained.

A clean of the case is attached for further takeup and reproducibility. It is running on CFDEM-5.x with OpenFOAM-5.x

Due to issues with the forum, the snapshot and case zip file could not be uploaded. Please find them at the following link:
https://mega.nz/file/XRIBXJrD#6uI5dk...P5F1CNb43lPt5Y
https://mega.nz/file/GcAngLTY#3Jr4N7...rXFim7QovO_f-U

Tried multiple ways but to no luck. Any help in this regard would be really appreciated.
Thanks in advance