Experimental investigation of wall pressure and arching behavior under surcharge pressure in mass-flow hoppers

Guo, Jie; Roberts, A. W.; Prigge, Jan-Dirk

doi:10.1016/j.powtec.2014.03.048

Cited by 20 publications

(6 citation statements)

References 9 publications

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“…Hopper arching is a classical challenge in bulk solid handling, a significant amount of experimental and numerical studies have been conducted in the literature. One of the focuses of these studies is the determination of the hopper critical outlet width for various materials (e.g., rocks, coals, ores, pharmaceutical particles, and ideal spherical beads). ,− Experimental characterization of a specific granular material is the most direct way to understand the flow behavior and quantify the critical outlet width. Yet, limited by the sensors on the hopper, experiments can only measure global flow response (e.g., flow rate, flow pattern) and cannot track the strain–stress behavior within the material.…”

Section: Introductionmentioning

confidence: 99%

Flow and Arching of Biomass Particles in Wedge-Shaped Hoppers

Jin

Klinger

et al. 2021

ACS Sustainable Chem. Eng.

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Poor understanding of the flow behavior of granular biomass material poses great challenges for the bioenergy industry, as the equipment functioning time is significantly reduced by handling issues like screw feeder clogging and hopper arching. In this work, the flow behavior of loblolly pine chips, including the mass flow rate and the critical outlet width, in a wedge-shaped hopper is investigated by combining physical experiments and numerical simulations. Comprehensive characterization of the flow response affected by the two material attributes (initial packing, particle density) and the three operational parameters (hopper outlet width, hopper inclination, and surcharge) is conducted. The results show that the hopper outlet width linearly controls the mass flow rate, while the hopper inclination angle controls the critical outlet size. The packing determines whether the flow is smooth or surging, and the surcharge-induced compaction creates flow impedance. The magnitude of these influences varies from a slender hopper with a low inclination angle to a flat-bottom silo. These findings provide guidance for hopper operation in the material handling industry and shed light on the construction of a novel design method for material handling equipment in biorefineries.

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Section: Introductionmentioning

confidence: 99%

Flow and Arching of Biomass Particles in Wedge-Shaped Hoppers

Jin

Klinger

et al. 2021

ACS Sustainable Chem. Eng.

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“…Hopper arching, a long-lasting challenge in bulk material handling, has been extensively investigated with both physical experiments and numerical simulations. For example, the hopper critical outlet width for flowing of conventional granular materials ranging from ideal spherical beads to engineering materials (e.g., pharmaceutical particles, rocks, coals, and ores) has been investigated. − Unfortunately, the arching behaviors of granular biomass materials are way different from those of conventional materials due to their distinctive characteristics (i.e., low particle density, high aspect ratio, high compressibility, and high shear resistance) . As a result, the widely used Jenike hopper design guide , usually overestimates the critical outlet width of hoppers for conventional granular materials, ,, but it constantly underestimates the critical arching outlet width for milled biomass materials. ,, …”

Section: Introductionmentioning

confidence: 99%

Wedge-Shaped Hopper Design for Milled Woody Biomass Flow

Jin

Saha

et al. 2022

ACS Sustainable Chem. Eng.

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The bioenergy industry has been challenged by unstable flow and transport of milled biomass in material handling operations. Handling issues such as hopper clogging and auger jamming are attributed to knowledge gaps between existing handling units designed for bulk solids and their suitability for milled biomass with high compressibility. This work investigates various flow behaviors of granular woody biomass in wedge-shaped hoppers. Hopper flow physical experiments and numerical simulations are conducted to study the influence of the critical material attributes and critical processing parameters on the flow pattern, arching, and throughput. The results show that (1) the preferred flow pattern, mass flow, can be achieved by controlling the material's internal friction angle, hopper inclination, and hopper wall friction; (2) hopper arching, governed by the competing gravity-driven force against flow resistance from material internal friction and material− wall friction, can be controlled by the hopper wall friction angle and the inclination angle; and (3) flow throughput can be accurately estimated from our empirical equation with inputs of hopper outlet geometry and particle-scale to bulk-scale material attributes. This study elucidates woody biomass flow physics and provides guidance for industrial equipment design.

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“…Therefore, the safety of the silo is important. It is widely known that concentric discharging at the silo bottom is the most desirable discharging way 2 – 5 . The idea that the dynamic pressure on the sidewall is greater than the static pressure during concentric discharging has been generally accepted, which may cause the silo’s structural failure and affect the stability of bulk solid handling.…”

Section: Introductionmentioning

confidence: 99%

Modified lateral pressure formula of shallow and circular silo considering the elasticities of silo wall and storage materials

Liang

2022

Sci Rep

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For the shallow and circular silo (SCS), when the aspect ratio is between 1.0 and 1.5, the lateral pressure especially dynamic pressure may cause destruction if the size of the silo is large. This paper proposed a modified calculation method of lateral pressure on the silo wall of SCS, considering the elasticities of silo wall and storage materials. The availability of shallow silo and deep silo methods, and the modified method were compared with the experiment and simulation. The results show that the Rankine’s formula is too conservative for the static lateral pressure, and the results of the modified method and Janssen formula are close to that of the experimental and simulation. For the dynamic lateral pressure calculation, Rankine theory is unsafe for the discharging load. The relative error of the dynamic lateral pressure based on Janssen theory is between 20 and 30%, which is too large. The dynamic lateral pressure calculated by the modified method is in good agreement with that of the experimental and simulation, and the relative error is less than 10%. Therefore, the modified method of lateral pressure formula is reasonable, which can provide guidance for the safety design of silo structure.

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Experimental investigation of wall pressure and arching behavior under surcharge pressure in mass-flow hoppers

Cited by 20 publications

References 9 publications

Flow and Arching of Biomass Particles in Wedge-Shaped Hoppers

Flow and Arching of Biomass Particles in Wedge-Shaped Hoppers

Wedge-Shaped Hopper Design for Milled Woody Biomass Flow

Modified lateral pressure formula of shallow and circular silo considering the elasticities of silo wall and storage materials

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