1134
Experimental and DEM Investigation of Non-Spherical Particle
Dynamics in Pseudo-2D Hopper Discharge
Aman Mittal, Ainkara Karthiga R, Narasimha Mangadoddy
Department of Chemical Engineering, Indian Institute of Technology Hyderabad,
Kandi, Sangareddy, Telangana, India
ABSTRACT: Gaining a profound insight into the impact of particle morphology on granular flow within
a gravity-driven hopper system holds paramount importance. This research explores a pseudo-2D hopper
configuration to delve into the dynamics of spherical and polyhedral-shaped particles. Employing image-
processing utilizing high-speed video cameras for experimental analysis and advanced Discrete Element
Modeling (DEM) simulation methods, including multi-sphere and polyhedral models, this study prioritizes the
investigation of deviations from typical spherical shapes. The study’s core objectives involve characterizing the
dynamics of particle flow within the hopper, analyzing mass flow rates and velocity profiles, and highlighting the
crucial role played by particle shape representation. To achieve these objectives, a combination of experimental
and simulation approaches is utilized, with in-house DEM simulation results being validated against experimental
data. Notably, our results clearly demonstrate a pattern of decreasing flow rates and slower particle velocities at
the hopper’s exit as the particles’ sphericity decreases. The experimental findings also highlight velocity profile
fluctuations resulting from the non-spherical particles, attributed to transient blockages and arching occurrences,
a phenomenon anticipated by the DEM techniques as well.
Keywords: DEM, Polyhedral, Multi-sphere, Particulate Flow System, Hopper flow
INTRODUCTION
The handling and processing of granular materials in phar-
maceutical, chemical, construction, mineral processing,
food processing industries, and mining industries require
critical domain knowledge. One-half of the products and
three-quarters of the raw materials in the industries are of
the granular form and are stored in silos and bunkers (Yang
and Hsiau 2001). The studies on granular transportation
available in the literature mainly focused on spherical par-
ticles, but real particles are mostly of non-spherical shapes.
The storage and discharge of these materials are handled
using hoppers &silos. Observing the hopper flows yields
knowledge of the full range of granular behaviour during
the discharge, from static packing within the bed, dense
to dilute phase flow through the opening, and a free-fall-
ing particle stream (Hilton and Cleary 2011). The hop-
pers observe two primary flow patterns: funnel flow and
mass flow. In the funnel flow, some particles flow towards
the hopper outlet while the rest are stationary there is no
interaction between the flow channel and the wall. This
is observed when there is high friction between particles
and walls, and the hopper bottom is nearly or entirely flat.
In the mass flow pattern, all the particles move down in
the hopper, as the walls are steep, and the friction between
the particle and the wall is low. Hence, no stagnant zone
is observed, and the flowing channel coincides with the
Experimental and DEM Investigation of Non-Spherical Particle
Dynamics in Pseudo-2D Hopper Discharge
Aman Mittal, Ainkara Karthiga R, Narasimha Mangadoddy
Department of Chemical Engineering, Indian Institute of Technology Hyderabad,
Kandi, Sangareddy, Telangana, India
ABSTRACT: Gaining a profound insight into the impact of particle morphology on granular flow within
a gravity-driven hopper system holds paramount importance. This research explores a pseudo-2D hopper
configuration to delve into the dynamics of spherical and polyhedral-shaped particles. Employing image-
processing utilizing high-speed video cameras for experimental analysis and advanced Discrete Element
Modeling (DEM) simulation methods, including multi-sphere and polyhedral models, this study prioritizes the
investigation of deviations from typical spherical shapes. The study’s core objectives involve characterizing the
dynamics of particle flow within the hopper, analyzing mass flow rates and velocity profiles, and highlighting the
crucial role played by particle shape representation. To achieve these objectives, a combination of experimental
and simulation approaches is utilized, with in-house DEM simulation results being validated against experimental
data. Notably, our results clearly demonstrate a pattern of decreasing flow rates and slower particle velocities at
the hopper’s exit as the particles’ sphericity decreases. The experimental findings also highlight velocity profile
fluctuations resulting from the non-spherical particles, attributed to transient blockages and arching occurrences,
a phenomenon anticipated by the DEM techniques as well.
Keywords: DEM, Polyhedral, Multi-sphere, Particulate Flow System, Hopper flow
INTRODUCTION
The handling and processing of granular materials in phar-
maceutical, chemical, construction, mineral processing,
food processing industries, and mining industries require
critical domain knowledge. One-half of the products and
three-quarters of the raw materials in the industries are of
the granular form and are stored in silos and bunkers (Yang
and Hsiau 2001). The studies on granular transportation
available in the literature mainly focused on spherical par-
ticles, but real particles are mostly of non-spherical shapes.
The storage and discharge of these materials are handled
using hoppers &silos. Observing the hopper flows yields
knowledge of the full range of granular behaviour during
the discharge, from static packing within the bed, dense
to dilute phase flow through the opening, and a free-fall-
ing particle stream (Hilton and Cleary 2011). The hop-
pers observe two primary flow patterns: funnel flow and
mass flow. In the funnel flow, some particles flow towards
the hopper outlet while the rest are stationary there is no
interaction between the flow channel and the wall. This
is observed when there is high friction between particles
and walls, and the hopper bottom is nearly or entirely flat.
In the mass flow pattern, all the particles move down in
the hopper, as the walls are steep, and the friction between
the particle and the wall is low. Hence, no stagnant zone
is observed, and the flowing channel coincides with the