XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1139
spheres as shown in Figure 2 (c). The multi-sphere particle
approximation for cube is comparatively smoother near the
edges. A sphere of diameter equaling the cube side length
inscribed at the center and 8 spheres surrounding that
along the walls of the cubes. The DEM parameters based
on the particle properties were calibrated by analyzing the
effect of these parameters on the mass discharge rate. The
fine- tuned parameters are given in Table 2. After the simu-
lation was run, the results were analyzed to estimate the
mass discharge rate and the velocity contours validate with
the experimental data. The coarse graining approach was
used to calculate the velocity fields of the particles from the
simulation results.
RESULTS AND DISCUSSIONS
Validation of Spherical DEM with Experiments
Mass discharge of the spherical particles from the hopper
was recorded for every 0.5 s and was plotted as the mass
discharge percentage with time and compared with the
DEM simulation results. The experimental and the DEM
simulation data agree well for the mass discharge, as shown
in Figure 3. The slight delay in recording the weight of the
particles discharged during the experiments accounts for
the initial overprediction of the discharge rate by DEM
simulations. The deviation between the experimental dis-
charge rate and simulation results are within the range of
0.21% to 7.66%. The obtained velocity contours for the
spheres discharged from the hopper from the experiment
and simulations are displayed in Figure 4. As the hopper
was making 45o with the base, the flow pattern observed
inside the hopper was funnel flow. There was a distinct
channel flow occurring inside the hopper near the cen-
treline of the hopper with some stagnant material in the
outer zone. The experimental data as well as the simulation
agree with this, although the stagnant zones appearing from
Table 2. Parameters used in the DEM study
S.No. Properties Particle 1 Particle 2
1 Poisson ratio 0.45 0.45
2 Youngs modulus 5*106 Pa 5*106 Pa
3 Coefficient of
restitution
0.6 0.8
4 Coefficient of friction 0.3 0.2
Figure 3. Mass discharge %vs time for spherical particles
discharge from the hopper
Figure 4. Velocity contours for spherical particles discharge from the hopper (a) Experiment and (b) DEM simulation
spheres as shown in Figure 2 (c). The multi-sphere particle
approximation for cube is comparatively smoother near the
edges. A sphere of diameter equaling the cube side length
inscribed at the center and 8 spheres surrounding that
along the walls of the cubes. The DEM parameters based
on the particle properties were calibrated by analyzing the
effect of these parameters on the mass discharge rate. The
fine- tuned parameters are given in Table 2. After the simu-
lation was run, the results were analyzed to estimate the
mass discharge rate and the velocity contours validate with
the experimental data. The coarse graining approach was
used to calculate the velocity fields of the particles from the
simulation results.
RESULTS AND DISCUSSIONS
Validation of Spherical DEM with Experiments
Mass discharge of the spherical particles from the hopper
was recorded for every 0.5 s and was plotted as the mass
discharge percentage with time and compared with the
DEM simulation results. The experimental and the DEM
simulation data agree well for the mass discharge, as shown
in Figure 3. The slight delay in recording the weight of the
particles discharged during the experiments accounts for
the initial overprediction of the discharge rate by DEM
simulations. The deviation between the experimental dis-
charge rate and simulation results are within the range of
0.21% to 7.66%. The obtained velocity contours for the
spheres discharged from the hopper from the experiment
and simulations are displayed in Figure 4. As the hopper
was making 45o with the base, the flow pattern observed
inside the hopper was funnel flow. There was a distinct
channel flow occurring inside the hopper near the cen-
treline of the hopper with some stagnant material in the
outer zone. The experimental data as well as the simulation
agree with this, although the stagnant zones appearing from
Table 2. Parameters used in the DEM study
S.No. Properties Particle 1 Particle 2
1 Poisson ratio 0.45 0.45
2 Youngs modulus 5*106 Pa 5*106 Pa
3 Coefficient of
restitution
0.6 0.8
4 Coefficient of friction 0.3 0.2
Figure 3. Mass discharge %vs time for spherical particles
discharge from the hopper
Figure 4. Velocity contours for spherical particles discharge from the hopper (a) Experiment and (b) DEM simulation