Jamming probability of granular flow in 3D hopper with shallow columns: DEM simulations
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ORIGINAL PAPER
Jamming probability of granular flow in 3D hopper with shallow columns: DEM simulations Su‑San Park1 · Eung Soo Kim1 Received: 12 November 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract We performed a numerical study of the jamming that stops the flow of granular material from a three-dimensional hopper discharging due to gravity. When the hopper outlet is not much larger than the particles, granular material clogs the hopper outlet due to the formation of an arch or dome. For a wide range of particle diameters, we obtained the size distribution of the “avalanche,” defined as the number of particles that fall before jamming. We repeated this process through a discrete element method model verified with a simple experiment. From these distributions, we determined the probability of the flow jamming before N particles pass through the hopper. As the ratio between the hopper outlet diameter and the particle diameter increases, the probability that an arch will block the outlet decreases. We show here that the probability of one particle passing through the hopper is not constant when there are not sufficient particles. Then, we propose a new model that can quantify changes in particle passing probability. Using this model, we derive the particle passing probability in a hopper with shallow columns and confirm that the probability of one particle passing through the hopper is closely related to the pressure acting on the bottom of the hopper. Keywords Discrete element method · Granular material · Jamming · Janssen effect · Probability
1 Introduction Jamming, a phenomenon that clogs a space when discrete objects pass through a narrow passage, is a general phenomenon that occurs in various fields. The objects could be animals [1], pedestrians [2, 3], insects [4], red blood cells [5], bacteria [6], cars [7], or grains [8]. When jamming occurs, objects can no longer flow through the hopper unless they are agitated externally. Therefore, jamming should be understood and predicted effectively to avoid related issues in practice. However, despite the many theoretical and experimental studies in granular material jamming conducted to date, the conversion from flowing to jamming and how it occurs is still not fully understood. With advances in experimental and computational techniques, recent studies [9, 10] have clearly demonstrated that jamming occurs due to the formation of an arch at the hopper outlet. Since then,
* Eung Soo Kim [email protected] 1
Department of Nuclear Engineering, Seoul National University, 559 Gwanak‑ro, Gwanak‑gu, Seoul, South Korea
quantitative evaluations of factors affecting arch formation have been studied in various ways [11, 12]. Some studies recently attempted a more theoretical approach to the interpretation of jamming. These studies assumed that the probability of a particle passing through a hopper is unchanged regardless of the number of particles remaining [13–15]. This assumption is inferred from the general characteristics of granular m
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