Large scale simulation of particle coating using coupled CFD-DEM
Typ
Examensarbete för masterexamen
Program
Applied mechanics (MPAME), MSc
Publicerad
2020
Författare
Hariharan, Anand
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Spouted fluidized beds are widely used for particle coating because of its excellent mixing rates and
favorable heat and mass transfer characteristics. The combination of Computational Fluid Dynamics
(CFD) and the Discrete Element Method (DEM) has previously been employed for simulation of
the complex phenomena of such processes. However, simulating a fluidized bed on a large scale
with DEM requires exceptional computational power as all the interactions between the particles
are fully resolved. In addition, simulating the spray droplets further increases the computational
demand. Accordingly, coupled DEM and CFD simulations with a well resolved spray have typically
been limited to system sizes from a few thousand up to much less than a million particles.
The goal of the current thesis was to perform spray coating simulations on systems with more than 1
million particles, including a Lagrangian spray phase and a well resolved fluid. The thesis is carried
out using the DEM-CFD solver IPS FluidizationTM developed at Fraunhofer Chalmers Centre. The
solver is based on an in-house DEM code and the in-house immersed boundary CFD code IBOFlowR
.
Due to heavy use of the Graphical Processing Unit (GPU), the code allows simulating a large number
of particles and a well resolved fluid on a standard desktop computer.
In the first part of the thesis, single spout simulations are carried out to validate the coupled solver.
The simulations show excellent agreement with the experimental data available in the open literature.
Further, 1D studies are conducted for verifying the heat transfer model. The numerical predictions are
shown to be accurate based on comparisons with analytical 1D models. Finally, large scale simulations
including the spray and drying are conducted on a Wurster bed system with both the particles and
the spray considered in a Lagrangian sense. The simulations show the versatility of the tool and the
possibility to e.g. characterize the particle coating thickness in terms of the original particle size, as
well as it proves applicability to cases with more than 1 million particles.
Beskrivning
Ämne/nyckelord
CFD , DEM , particle coating , Wurster bed , fluidization , GPU