1136 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
computational cost associated with contact detection and
resolution (Fraige, Langston, and Chen 2008). The poly-
hedral DEM approach has been used to study the particle
flow inside the hopper. Fraige, Langston, and Al-Khatib
2011 in their work implemented polyhedral DEM to study
the discharge of octahedral and tetrahedral particles from a
flat-bottomed rectangular hopper and studied how increase
in particles’ angularity reduced the mass discharge from the
hopper. Similar observation was made by Höhner, Wirtz,
and Scherer 2012 in their study and they found that the
increase in angularity of the particles also caused an increase
in the residual mass quantity when the flat-bottomed hop-
per was used. Kwon and Ryu 2020 used this approach to
study the discharge characteristics of rod-shaped particles
with triangular, square, pentagonal, and hexagonal cross-
sections inside a hopper and observed that the particle
packing property significantly influenced the discharge of
the non-spherical particles.
The flow of spherical particles through hopper has been
studied well in the literature (Ahn et al., 2007, Kruggel-
Emden et al., 2009, Hilton and Cleary 2011, Fraige,
Langston, and Al-Khatib 2011, Kumar et al., 2018, 2020
Kobyłka et al., 2021 Méndez, Hidalgo and Maza, 2021).
Meanwhile, non-spherical particle dynamics is gaining the
required attention. The discharge characteristics of binary
particles in the rectangular hopper with an inclined bot-
tom were studied by Zhang et al., 2021. They found that
the mass discharge rate increased exponentially with the
decrease in the hopper angle. When the hopper was filled
with different single-component particle systems, the dis-
charge rates in the early stage were constant. Jian and Gao
2023 studied the discharge characteristics while handling
the spherical, non-spherical and their binary mixtures in
a flat bottom hopper and studied the residual inclination
angle of particles the angle was higher for those particles
with smaller sphericity and higher particle density. Lattanzi
and Stickel 2020 observed that the order parameter within
the hopper increases significantly during the discharge, and
the rod-shaped particles undergo shear-induced alignment
with the long dimension orthogonal to the outflow plane.
The introduction of the rod-shaped particles increased the
discharge rate fluctuations, indicating the incipient jam-
ming. Fraige, Langston, and Al-Khatib 2011 observed a
reduction in flow rate of up to 49% and 41% for tetrahe-
dral and octahedral particles, respectively.
In this work, the focus is on studying the influence of
the particle shape on the flow behaviour inside the hopper.
Spherical and cubic-shaped particle flow are studied using
experimental set-up and validated using the in-house devel-
oped GPU-based DEM simulations. The particle shape is
implemented using the multi-sphere and the polyhedral
based DEM simulations. The particle shape effect during
the discharge is studied by varying the sphericity param-
eter while keeping the aspect ratio constant. The quantita-
tive comparisons are made in-terms of the mass discharge
curve and the velocity contours to understand the effects
produced by the flow of non-spherical particles inside the
hopper. The study also emphasizes the importance of the
particle shape during the hopper discharge flow by provid-
ing insights into the flow disturbances that occur during
the discharge of non-spherical particles. The flow pattern
inside the hopper is also analyzed with the varying particle
shapes.
METHODOLOGY
Experimental Methodology
Materials and Methods
The experimental hopper discharge study was conducted
to study the flow behaviour of spherical and non-spherical
particles inside the hopper by recording their motion using
a high-speed video camera. For this study, a pseudo-2D
hopper with an 8 mm width was fabricated using transpar-
ent acrylic sheets. The hopper makes a 45o with the base,
and the orifice opening is 72 mm long. The experimental
setup is shown in Figure 1(c). Photron high speed video
camera was placed in-front of the hopper as shown in
the schematics in Figure 1(a). LED light was set-up from
behind the hopper to illuminate the flow of particles from
the hopper and a diffuser sheet was placed in-between the
hopper and the LED light to allow for even distribution
of the light. A vessel was placed on a weighing scale under
the hopper at a height of 20 cm from the hopper orifice to
collect and measure the weight of the particles flowing from
the hopper. A camera was positioned to record the weight
being obtained from the weighing balance. The particles
used in this study are spherical particles of 6 mm diameter
and 1293 kg/m3 density and cubes of 5 mm size and 1216
kg/m3 density. The cubic-shaped particles were obtained by
cutting the 5 mm thick acrylic sheets into 5 mm × 5 mm
sized particles by using a laser cutting machine. The density
of these particles was calculated by measuring their mass
and volume. The properties of the particle used in this
study are presented in Table 1.
While performing the experiment, the particles were
initially filled to the brim of the hopper, and at time t=0 s,
the hopper bottom lid was opened. At the exact time, the
high-speed video camera was used to start recording the
motion of the particles with 640-pixel × 640-pixel resolu-
tions at a rate of 3000 FPS. The area covered from the High
Speed Video Camera is 0.32 m × 0.32 m from the hopper
computational cost associated with contact detection and
resolution (Fraige, Langston, and Chen 2008). The poly-
hedral DEM approach has been used to study the particle
flow inside the hopper. Fraige, Langston, and Al-Khatib
2011 in their work implemented polyhedral DEM to study
the discharge of octahedral and tetrahedral particles from a
flat-bottomed rectangular hopper and studied how increase
in particles’ angularity reduced the mass discharge from the
hopper. Similar observation was made by Höhner, Wirtz,
and Scherer 2012 in their study and they found that the
increase in angularity of the particles also caused an increase
in the residual mass quantity when the flat-bottomed hop-
per was used. Kwon and Ryu 2020 used this approach to
study the discharge characteristics of rod-shaped particles
with triangular, square, pentagonal, and hexagonal cross-
sections inside a hopper and observed that the particle
packing property significantly influenced the discharge of
the non-spherical particles.
The flow of spherical particles through hopper has been
studied well in the literature (Ahn et al., 2007, Kruggel-
Emden et al., 2009, Hilton and Cleary 2011, Fraige,
Langston, and Al-Khatib 2011, Kumar et al., 2018, 2020
Kobyłka et al., 2021 Méndez, Hidalgo and Maza, 2021).
Meanwhile, non-spherical particle dynamics is gaining the
required attention. The discharge characteristics of binary
particles in the rectangular hopper with an inclined bot-
tom were studied by Zhang et al., 2021. They found that
the mass discharge rate increased exponentially with the
decrease in the hopper angle. When the hopper was filled
with different single-component particle systems, the dis-
charge rates in the early stage were constant. Jian and Gao
2023 studied the discharge characteristics while handling
the spherical, non-spherical and their binary mixtures in
a flat bottom hopper and studied the residual inclination
angle of particles the angle was higher for those particles
with smaller sphericity and higher particle density. Lattanzi
and Stickel 2020 observed that the order parameter within
the hopper increases significantly during the discharge, and
the rod-shaped particles undergo shear-induced alignment
with the long dimension orthogonal to the outflow plane.
The introduction of the rod-shaped particles increased the
discharge rate fluctuations, indicating the incipient jam-
ming. Fraige, Langston, and Al-Khatib 2011 observed a
reduction in flow rate of up to 49% and 41% for tetrahe-
dral and octahedral particles, respectively.
In this work, the focus is on studying the influence of
the particle shape on the flow behaviour inside the hopper.
Spherical and cubic-shaped particle flow are studied using
experimental set-up and validated using the in-house devel-
oped GPU-based DEM simulations. The particle shape is
implemented using the multi-sphere and the polyhedral
based DEM simulations. The particle shape effect during
the discharge is studied by varying the sphericity param-
eter while keeping the aspect ratio constant. The quantita-
tive comparisons are made in-terms of the mass discharge
curve and the velocity contours to understand the effects
produced by the flow of non-spherical particles inside the
hopper. The study also emphasizes the importance of the
particle shape during the hopper discharge flow by provid-
ing insights into the flow disturbances that occur during
the discharge of non-spherical particles. The flow pattern
inside the hopper is also analyzed with the varying particle
shapes.
METHODOLOGY
Experimental Methodology
Materials and Methods
The experimental hopper discharge study was conducted
to study the flow behaviour of spherical and non-spherical
particles inside the hopper by recording their motion using
a high-speed video camera. For this study, a pseudo-2D
hopper with an 8 mm width was fabricated using transpar-
ent acrylic sheets. The hopper makes a 45o with the base,
and the orifice opening is 72 mm long. The experimental
setup is shown in Figure 1(c). Photron high speed video
camera was placed in-front of the hopper as shown in
the schematics in Figure 1(a). LED light was set-up from
behind the hopper to illuminate the flow of particles from
the hopper and a diffuser sheet was placed in-between the
hopper and the LED light to allow for even distribution
of the light. A vessel was placed on a weighing scale under
the hopper at a height of 20 cm from the hopper orifice to
collect and measure the weight of the particles flowing from
the hopper. A camera was positioned to record the weight
being obtained from the weighing balance. The particles
used in this study are spherical particles of 6 mm diameter
and 1293 kg/m3 density and cubes of 5 mm size and 1216
kg/m3 density. The cubic-shaped particles were obtained by
cutting the 5 mm thick acrylic sheets into 5 mm × 5 mm
sized particles by using a laser cutting machine. The density
of these particles was calculated by measuring their mass
and volume. The properties of the particle used in this
study are presented in Table 1.
While performing the experiment, the particles were
initially filled to the brim of the hopper, and at time t=0 s,
the hopper bottom lid was opened. At the exact time, the
high-speed video camera was used to start recording the
motion of the particles with 640-pixel × 640-pixel resolu-
tions at a rate of 3000 FPS. The area covered from the High
Speed Video Camera is 0.32 m × 0.32 m from the hopper
