Proceedings of the 8th International Conference on CFD in Oil and Gas, Metallurgical and Process Industries, Trondheim
Original Kurzfassung:
In this paper we present a multi-purpose CFD-DEM
framework to simulate coupled fluid-granular systems.
The motion of the particles is resolved by means of the
Discrete Element Method (DEM), and the
Computational Fluid Dynamics (CFD) method is used
to calculate the interstitial fluid flow. The focus of this
paper is to show the ability of this coupled CFD-DEM
framework to handle different scales and physical
phenomena.
Firstly, with ?approach A? we show the applicability of
the coupling framework for flows, where the particle
sizes are significantly smaller than the CFD grid. The
motion of an incompressible fluid phase in the presence
of a secondary particulate phase is then governed by a
modified set of Navier-Stokes-Equations accounting for
the volume fraction á occupied by the fluid, and a
momentum exchange term
pf
R.
Secondly, with ?approach B? we show the applicability
of the coupling framework to the case of large particles
and fine computational grids using the fictitious domain
/ immersed boundary method. In the first step the
incompressible Navier-Stokes equations are solved over
the whole domain. The next task is to correct the
bodies? velocities in the affected cells (i.e. those cells,
which are covered by the immersed bodies). Finally a
correction-operation is applied to account for the
divergence-free condition of the flow field.
Both approaches are successfully tested against
analytics as well as experimental data. Application
examples of the coupling are shown, ranging from to
floatation and fluidised beds (approach A) to
sedimentation (approach B).
Concluding, we show the versatility and applicability of
the open source CFD-DEM framework (CFDEM, 2011)
which is based on the DEM code LIGGGHTS
(LIGGGHTS, 2011) and the open source CFD toolbox
OpenFOAM® (OpenCFD Ltd., 2009). LIGGGHTS and
an initial release of the CFD-DEM coupling are
available for public download.