Storage and Flow of Solids
01 Jan 1964-
About: The article was published on 1964-01-01 and is currently open access. It has received 585 citations till now. The article focuses on the topics: Flow (mathematics).
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01 Jan 2021
TL;DR: In this article, the flow behavior of a bulk solid can be described using physical parameters such as unconfined yield strength (compressive strength), internal friction, effective angle of internal friction and bulk density.
Abstract: The flow behavior of a bulk solid can be described using physical parameters such as unconfined yield strength (compressive strength), internal friction, effective angle of internal friction and bulk density. In addition, there is time consolidation, which describes the increase in strength when the bulk solid is stored for a long period of time under compressive stress acting on the bulk solid, as well as wall friction, i.e., the friction between a bulk solid and a solid surface (e.g., the wall of a hopper). The variables mentioned are determined by measuring so-called yield loci, time yield loci and wall yield loci. From the bulk solid’s strength, a key figure for assessing flowability can be derived, the applicability and origin of which is discussed. In addition to the variables mentioned, which depend on the stress acting on the bulk solid, the basic principles for their measurement are explained.
11 citations
01 Jan 2000
TL;DR: Ineffective blending, or the inability to control particle segregation, is always costly in terms of rejected materials, extra blending time, and defective end products.
Abstract: Obtaining a uniform blend of dry bulk solids, and maintaining that blend through downstream equipment, is a problem faced daily by engineers and operators in industries as varied as pharmaceuticals, foods, plastics, fiberglass, and battery production. Ineffective blending, or the inability to control particle segregation, is always costly in terms of rejected materials, extra blending time, and defective end products.
11 citations
01 Jan 2003
TL;DR: The fundamentals of cohesive powder consolidation and flow behavior using a reasonable combination of particle and continuum mechanics are explained in this paper, where the influence of elastic-plastic repulsion in particle contacts is demonstrated.
Abstract: The fundamentals of cohesive powder consolidation and flow behaviour using a reasonable combination of particle and continuum mechanics are explained. By means of the model “stiff particles with soft contacts” the influence of elastic-plastic repulsion in particle contacts is demonstrated. With this as the physical basis, universal models are presented which include the elastic-plastic and viscoplastic particle contact behaviours with adhesion, load-unload hysteresis and thus energy dissipation, a history dependent, non-linear adhesion force model, easy to handle constitutive equations for powder elasticity, incipient powder consolidation, yield and cohesive steady-state flow, consolidation and compression functions, compression and preshear work. Exemplary, the flow properties of a cohesive limestone powder (d50 = 1.2 µm) are shown. These models are also used to evaluate shear cell test results as constitutive functions for computer aided apparatus design for reliable powder flow. Finally, conclusions are drawn concerning particle stressing, powder handling behaviours and product quality assessment in processing industries.
11 citations
TL;DR: In this article, the authors investigated the capturing of fine dry particles by means of simplified experiments using a drop-weight tester and found that an increase of powder flowability and material fineness were shown to enhance the displacement of the particles out of the zone between a static plate and a falling ball.
11 citations
TL;DR: The Wolfram Project Demonstration as discussed by the authors shows how to find the Unconfined Yield Stress and Major Consolidation Stress of a cohesive powder's compact by constructing two Mohr semicircles that are tangential to the YLC; the first passing through the origin (0,0) and the second at the consolidation conditions (σ 0,τ0).
11 citations