6. Conclusions
This paper has briefly outlined some of the developments
that have occurred for hydrocyclone CFD as well
as key challenges that remain to be addressed in the
development of a complete and validated model of the
hydrocyclone flow-field. Key development needs to have
been identified for the detailed turbulence and multiphase
modelling through to embedding of such into an
automatic hydrocyclone design code. Although research
time-scales for some aspects of the proposed research
are long term, some technologies which could contribute
to remarkable progress of hydrocyclone performance
simulation, are available. Therefore, a short term realizable
algorithm could include the following components:
Three-dimensional unstructured grid tool in order
to retain geometrical flexibility, particularly in the context
of multi-objective design.
Full coupling of the fluid and particle phases using
the approach of Patankar and Joseph (2001). Their
approach incorporates a particle stress term to prevent
the particle volume fraction from exceeding closepacking
limit. They treated the particle phase as both a
continuum and as discrete particles with particle properties
mapped to and from the Eulerian grid consistently.
They demonstrated their approach for dilute and
concentrated size distributions utilizing particle probability-
distribution functions governed by the Liouville
equation which conserves particle numbers. The
numerical method implicitly couples phases through interphase momentum transfer and is considerably less
expensive computationally, for dense particle flows than
DNS.
Air-core modelling with capture of the liquid–gas
interface by means of the level set method of Osher and
Sethian (1988). This is relatively simple and versatile
approach for computing and analyzing the motion of an
interface in three dimensions. Caiden et al. (2001) further
developed this approach for the two-phase flow
regime addressing the boundary conditions and coupling
at the compressible/incompressible interface