XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3843
suggests there is a reasonably strong correlation between the
simulation and the experiment in the bulk bed region.
Velocity Field
Velocity profiles play a crucial role in characterising shear
rates, which are fundamental in the quest for a comprehen-
sive theory on dense granular flows—a concept currently
lacking in the existing literature (Kumaran, 2004).
In Figure 5, the velocity profiles of glass bead trajec-
tories are depicted at various viscosities and drum critical
speeds (Rose and Sullivan, 1957). The vectors are truncated
below the free surface due to measurement uncertainties
in the cataracting region. Velocity vectors are represented
with lengths ranging from 0 m/s (short, blue vectors) to
1.5 m/s (long, red vectors). Consistently, higher drum criti-
cal speeds correspond to an increased proportion of red vec-
tors within the flowing layer. This is indicative of enhanced
particle velocities in response to elevated drum speeds.
The observed effect on the shape of the free surface
aligns with expectations. As drum speeds increase, the
flowing layer exhibits more prominent red vectors, indi-
cating higher velocities. This heightened flow dynamic is
associated with a more pronounced shape of the free sur-
face. Specifically, at higher viscosities, the shoulder region
becomes more distinguishable compared to the toe region.
The asymmetry in the shape of the free surface, character-
ised by the enhanced shoulder region, is attributed to the
interplay between increased viscosity and elevated drum
speeds. The combined effect influences the distribution
and dynamics of the particles, impacting the velocity vec-
tors and shaping the overall behaviour of the dense granular
flow.
Figure 6 indicates the glass bead velocity vectors derived
from DEM-SPH coupled simulations whilst Figure 7, per
Alizadeh et al. (2014), displays the relative velocity vector
error analysis for the 10mm beads at different mill speeds.
Figure 5. PEPT glass bead velocity vectors at various speeds and viscosities
suggests there is a reasonably strong correlation between the
simulation and the experiment in the bulk bed region.
Velocity Field
Velocity profiles play a crucial role in characterising shear
rates, which are fundamental in the quest for a comprehen-
sive theory on dense granular flows—a concept currently
lacking in the existing literature (Kumaran, 2004).
In Figure 5, the velocity profiles of glass bead trajec-
tories are depicted at various viscosities and drum critical
speeds (Rose and Sullivan, 1957). The vectors are truncated
below the free surface due to measurement uncertainties
in the cataracting region. Velocity vectors are represented
with lengths ranging from 0 m/s (short, blue vectors) to
1.5 m/s (long, red vectors). Consistently, higher drum criti-
cal speeds correspond to an increased proportion of red vec-
tors within the flowing layer. This is indicative of enhanced
particle velocities in response to elevated drum speeds.
The observed effect on the shape of the free surface
aligns with expectations. As drum speeds increase, the
flowing layer exhibits more prominent red vectors, indi-
cating higher velocities. This heightened flow dynamic is
associated with a more pronounced shape of the free sur-
face. Specifically, at higher viscosities, the shoulder region
becomes more distinguishable compared to the toe region.
The asymmetry in the shape of the free surface, character-
ised by the enhanced shoulder region, is attributed to the
interplay between increased viscosity and elevated drum
speeds. The combined effect influences the distribution
and dynamics of the particles, impacting the velocity vec-
tors and shaping the overall behaviour of the dense granular
flow.
Figure 6 indicates the glass bead velocity vectors derived
from DEM-SPH coupled simulations whilst Figure 7, per
Alizadeh et al. (2014), displays the relative velocity vector
error analysis for the 10mm beads at different mill speeds.
Figure 5. PEPT glass bead velocity vectors at various speeds and viscosities