1140 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
the simulation data are quite distinct. The velocity magni-
tude is maximum near the hopper’s orifice opening. The
simulation slightly over-predicts the velocity magnitude
near the orifice. The velocity values at three different heights
in the hopper is shown in Figure 5. The DEM overpredicts
the velocity values near the orifice, however as the height
from the hopper-bottom increases, the DEM predictions
are within the range of the experiments. At height h =0 m,
near the walls, the variation is 3.75%, however along the
centreline the variation is at the maximum. Similarly, as the
height increases the variation is maximum at the centre and
away from the centre the deviation is less. The funnel flow
behaviour of the particles inside the hopper is one factor
for this variation across the hopper. There is a major devia-
tions at the height of 0.312 m. The experimental values
at this height might be influenced by the less illumination
received in this area from the LED light. The inaccuracies
can also be accounted from the error during the post-pro-
cessing of the obtained video using the PIVLab because of
the noise in the video and variation in the particle illumi-
nation. During experiments, additional factors like varying
particles’ and the hopper walls roughness played some role
in having varying particle-wall friction and reducing the
velocity magnitudes.
Validation of Non-Spherical DEM with Experiments
The experimental study of the cubes discharge showed arch
formation near the orifice of the hopper as depicted in the
Figure 6 (a). The flow of the particles from the experimen-
tal and DEM simulations are presented in the Figure 6
(b) which shows that the multi-sphere DEM discharged
the particles faster than the experimental case. The multi-
sphere DEM discharged the faste These non-spherical par-
ticles experience higher contact forces which hinders the
movement of the particles inside the hopper. Arching was
shown to occur during the gravity discharge studies in the
hopper when the strength of the particles is greater than
the weight induced stresses (Jenike 1964 Stainforth and
Ashley 1973). This is more predominant with non-spheri-
cal particles as these particles show interlocking behaviour
preventing their free motion. The phenomenon was found
to recur most of the times, when the experiments were
repeated. Mostly the arching happened around 1 s duration
of the flow after the hopper lid was opened. The fully devel-
oped flow condition was not achieved at that time and the
initial packing inside the hopper was very closely packed.
The set-up was then manually tapped to redistribute the
particles evenly across the hopper and the experiment was
repeated. Refilling the particles inside the hopper was not
feasible as the particles were not freely moving in the initial
stage and were more inclined to arch again. This led to a
Figure 5. Velocity magnitude across the hopper at different heights for spherical particle discharge
the simulation data are quite distinct. The velocity magni-
tude is maximum near the hopper’s orifice opening. The
simulation slightly over-predicts the velocity magnitude
near the orifice. The velocity values at three different heights
in the hopper is shown in Figure 5. The DEM overpredicts
the velocity values near the orifice, however as the height
from the hopper-bottom increases, the DEM predictions
are within the range of the experiments. At height h =0 m,
near the walls, the variation is 3.75%, however along the
centreline the variation is at the maximum. Similarly, as the
height increases the variation is maximum at the centre and
away from the centre the deviation is less. The funnel flow
behaviour of the particles inside the hopper is one factor
for this variation across the hopper. There is a major devia-
tions at the height of 0.312 m. The experimental values
at this height might be influenced by the less illumination
received in this area from the LED light. The inaccuracies
can also be accounted from the error during the post-pro-
cessing of the obtained video using the PIVLab because of
the noise in the video and variation in the particle illumi-
nation. During experiments, additional factors like varying
particles’ and the hopper walls roughness played some role
in having varying particle-wall friction and reducing the
velocity magnitudes.
Validation of Non-Spherical DEM with Experiments
The experimental study of the cubes discharge showed arch
formation near the orifice of the hopper as depicted in the
Figure 6 (a). The flow of the particles from the experimen-
tal and DEM simulations are presented in the Figure 6
(b) which shows that the multi-sphere DEM discharged
the particles faster than the experimental case. The multi-
sphere DEM discharged the faste These non-spherical par-
ticles experience higher contact forces which hinders the
movement of the particles inside the hopper. Arching was
shown to occur during the gravity discharge studies in the
hopper when the strength of the particles is greater than
the weight induced stresses (Jenike 1964 Stainforth and
Ashley 1973). This is more predominant with non-spheri-
cal particles as these particles show interlocking behaviour
preventing their free motion. The phenomenon was found
to recur most of the times, when the experiments were
repeated. Mostly the arching happened around 1 s duration
of the flow after the hopper lid was opened. The fully devel-
oped flow condition was not achieved at that time and the
initial packing inside the hopper was very closely packed.
The set-up was then manually tapped to redistribute the
particles evenly across the hopper and the experiment was
repeated. Refilling the particles inside the hopper was not
feasible as the particles were not freely moving in the initial
stage and were more inclined to arch again. This led to a
Figure 5. Velocity magnitude across the hopper at different heights for spherical particle discharge