Learning Forum

[ahock]

I am hoping to model a cyclone-like separation process. The challenge is that my feed material is non-spherical and quite large (4-8 mm) in comparison to fluid system (cyclone has a diameter of 15 cm), and I am not sure the best way to model this. I have tried doing this in Fluent using DPM and gotten some counterintuitive results. I now realize DPM requires the particles to be much smaller than the grid size, which is not feasible in my system. I also explored MPM, but (correct me if I am wrong) it appears this is only viable in flow with low Reynolds number which is not the case in cyclone flow. Are there any other particle tracking capabilities within Ansys Fluent or other Ansys products that can accomplish what I am trying to do? I understand the combo of large particles in turbulent flow is a challenging matter, and maybe not possible without introducing some simplifications. Please let me know if any other information is needed to provide help, thanks!

[Rob]

You've found the two "normal" Fluent options, and rightly concluded that neither is ideal. MPM has other limitations so I'd avoid that in most cases. 

Part of your problem is that the particles will interact with the flow in an interesting way, and will effect the turbulence and more general flow field. For one, they'll be larger than the flow boundary layer. The Rocky semi-resolved model coupled with Fluent is likely the best option but adding in the remeshing etc is going to make it an expensive calculation. 

[ahock]

Thanks, Rob. That is what I had suspected but wanted to be sure. I will try out Ansys Rocky