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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TL;DR: In this article, a number of experimental studies with dust aggregates formed from micron-size quartz grains are reported, and they confirm in laboratory collision experiments an earlier finding that producing macroscopic bodies by the random impact of sub-mm aggregates results in a well-defined upperfilling factor of 0.31 \pm 0.01.
Abstract: The first macroscopic bodies in protoplanetary disks are dust aggregates. We report on a number of experimental studies with dust aggregates formed from micron-size quartz grains. We confirm in laboratory collision experiments an earlier finding that producing macroscopic bodies by the random impact of sub-mm aggregates results in a well-defined upper-filling factor of 0.31 \pm 0.01. Compared to earlier experiments, we increase the projectile mass by about a factor of 100. The collision experiments also show that a highly porous dust-aggregate can retain its highly porous core if collisions get more energetic and a denser shell forms on top of the porous core. We measure the mechanical properties of cm-sized dust samples of different filling factors between 0.34 and 0.50. The tensile strength measured by a Brazilian test, varies between 1 kPa and 6 kPa. The sound speed is determined by a runtime measurement to range between 80 m/s and 140 m/s while Young's modulus is derived from the sound speed and varies between 7MPa and 25MPa. The samples were also subjected to quasi-static omni- and uni-directional compression todetermine their compression strengths and flow functions. Applied to planet formation, our experiments provide basic data for future simulations, explain the specific collisional outcomes observed in earlier experiments, and in general support a scenario where collisional growth of planetesimals is possible.
53 citations
TL;DR: In this paper, the authors have shown that if more research is not conducted on the characterization of the behavioral properties of biomasses, the sustainability of supply chains could be severely affected.
Abstract: Biomass comes from different sources and can be used for different purposes, for electricity generation, for transport fuels, for heating, as well as for the manufacturing of bio-based products. Nowadays, the European framework for energy calls for the use of biomass in electricity, heat, and transport (fuels), to reach 20% of all energy use from renewable sources by 2020. Therefore, the use of biomass should roughly have to double. If this is the case, large amounts of biomass will be mobilized and handling problems are expected to grow aligned with the increased use of biomass. Biomass is characterized because it does not flow well, packs easily, it can knit together, it is very dusty, and it is prone to self-heating and self-ignition, among others. If more research is not conducted on the characterization of the behavioral properties of biomasses, the sustainability of supply chains could be then severely affected.
53 citations
01 Jan 1987
TL;DR: In general it is more appropriate to model a bulk solid as a plastic solid than as a fluid continuum as mentioned in this paper, and the analogy is one that it is unwise to pursue.
Abstract: A good understanding of the nature of bulk solids flow is an essential prerequisite to the design of virtually any system involving the storage or handling of such materials. Observation of a bulk material discharging from a hopper or flowing under gravity along a steeply inclined channel will immediately suggest similarities to the behaviour of liquids. Whilst there are certainly some similarities between the flow characteristics of bulk solids and liquids, the analogy is one that it is unwise to pursue. In general it is more appropriate to model a bulk solid as a plastic solid than as a fluid continuum.
53 citations
TL;DR: In this article, a full-scale experimental study was conducted in which the patterns of solids flow and the flow channel boundaries were reliably quantified at the full scale and three materials were used: iron ore pellets, slag fines and crushed basalt.
53 citations
TL;DR: In this article, the fundamentals of cohesive particulate solids' consolidation and flow properties using a reasonable combination of particle and continuum mechanics by means of micro/macrotransition of the "characteristic particle contact" are explained.
Abstract: The fundamentals of cohesive particulate solids' consolidation and flow properties using a reasonable combination of particle and continuum mechanics by means of micro/macrotransition of the "characteristic particle contact" are explained. The adhesion force models of Tomas (2001a) are used to derive the stationary, instantaneous T S1 time yield loci and consolidation loci. Next, the uniaxial compressive strength c ( 1 ), effective angle of internal friction } e ( 1 ), and bulk density b ( 1 ) are obtained as powder constitutive functions. The approach has been shown to be effective for the data evaluation of cohesive powder flow properties, like a very cohesive titania nanopowder (surface diameter d s = 200 nm, solid density s = 3870kg/m 3 ) with the fit r 2 xy > 0.95. Finally, these models in combination with accurate shear cell test results are used as constitutive functions for computer-aided silo design for reliable flow.
53 citations