Flow Rate of Particles through Apertures Obtained from Self-Similar Density and Velocity Profiles

Janda, Álvaro; Zuriguel, Iker; Maza, Diego

doi:10.1103/physrevlett.108.248001

Cited by 179 publications

(245 citation statements)

References 23 publications

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“…The method is similar to that found in Ref. [24]. The vertical component of the speed v y is found by projection of the displacement vectors on the y-axis.…”

Section: High Gravity: 3d and 2d Set-upmentioning

confidence: 72%

“…A fine analysis can be found in the Ref. [24] and is also supported by the arch formation analysis [25,26].…”

Section: Introductionmentioning

confidence: 76%

“…(5) to the data [29,24]. It is important to note that this empirical profile works for all the considered apertures K. The figure Fig.8b presents the local area fraction φ(x) profiles.…”

Section: Local Parametersmentioning

confidence: 93%

“…[24], we prefer here to fit by a parabola centered at the middle of the aperture, i.e. φ(x) = φ(0) (…”

Section: Local Parametersmentioning

confidence: 99%

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Influence of the gravity on the discharge of a silo

et al. 2013

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We performed a series of experiments to investigate the flow of an assembly of non-cohesive spherical grains in both high and low gravity conditions (i.e. above and under the Earth's gravity). In high gravity conditions, we studied the flow of glass beads out of a cylindrical silo and the flow of metallic beads out of a vertical Hele-Shaw rectangular silo. Both silos were loaded in one of the gondolas of the Large Diameter Centrifuge facility (located at ESTEC) in which an apparent gravity up to 20 times the Earth's gravity can be established. To simulate low gravity conditions, we submitted a horizontal monolayer of metallic beads to the centrifuge force of a small rotation device (located at University of Liege). The influences of both gravity and aperture size on the mass flow were analysed in these various conditions. For the three systems (cylindrical silo, the Hele-shaw silo and the monolayer of beads), we demonstrated that (i) the square root scaling of the gravity found by Beverloo is relevant and (ii) the critical aperture size below which the flow is jammed does not significantly increase with the apparent gravity. Moreover, we studied in more details the Hele-Shaw silo in high gravity because this configuration allowed to determine local properties of the flow at the level of the aperture. We measured the velocity profiles and the packing fraction profiles for the various aperture sizes and apparent high gravities. We demonstrate the existence of a slip length for the flow at the level of the aperture. This later fact seems to result from the geometrical configuration of the silo.

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“…The method is similar to that found in Ref. [24]. The vertical component of the speed v y is found by projection of the displacement vectors on the y-axis.…”

Section: High Gravity: 3d and 2d Set-upmentioning

confidence: 72%

“…A fine analysis can be found in the Ref. [24] and is also supported by the arch formation analysis [25,26].…”

Section: Introductionmentioning

confidence: 76%

“…(5) to the data [29,24]. It is important to note that this empirical profile works for all the considered apertures K. The figure Fig.8b presents the local area fraction φ(x) profiles.…”

Section: Local Parametersmentioning

confidence: 93%

“…[24], we prefer here to fit by a parabola centered at the middle of the aperture, i.e. φ(x) = φ(0) (…”

Section: Local Parametersmentioning

confidence: 99%

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Influence of the gravity on the discharge of a silo

et al. 2013

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“…Shortly after, Janda et al [17] reported an experimental study of a discharge of monodisperse 1-mm diameter stainless steel beads in a twodimensional silo. By means of an image processing technique, they measured vertical velocity v z and solid fraction φ profiles at the outlet for a wide range of apertures.…”

Section: Introductionmentioning

confidence: 99%

Role of particle size in the kinematic properties of silo flow

2017

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We experimentally analyze the effect that particle size has on the mass flow rate of a quasi two-dimensional silo discharged by gravity. In a previous work, Janda et al. [Phys. Rev. Lett. 108, 248001 (2012)] introduced a new expression for the mass flow rate based on a detailed experimental analysis of the flow for 1-mm diameter beads. Here, we aim to extend these results by using particles of larger sizes and a variable that was not explicitly included in the proposed expression. We show that the velocity and density profiles at the outlet are self-similar and scale with the outlet size with the same functionalities as in the case of 1-mm particles. Nevertheless, some discrepancies are evidenced in the values of the fitting parameters. In particular, we observe that larger particles lead to higher velocities and lower packing fractions at the orifice. Intriguingly, both magnitudes seem to compensate giving rise to very similar flow rates. In order to shed light on the origin of this behavior we have computed fields of a solid fraction, velocity, and a kinetic-stress like variable in the region above the orifice.

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How nano‐scale roughness impacts the flow of grains influenced by capillary cohesion

et al. 2017

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SignificanceWe show that nano-scale changes in surface roughness affect the macro-scale (many-particle) behavior of granular materials influenced by cohesion. Macro-scale effects of roughness are investigated for conditions where cohesion is dominated by either humidity-induced or van der Waals-induced forces. Surface-topography measurements are used to calculate the relevant interparticle cohesive forces. The (force-dominated) macro-scale cohesion measurements are explained via the ratio of the predicted interparticle cohesive force to gravity, thus reinforcing the importance of roughness to cohesion.The values of u mf plotted in (b) are extracted from (a). Increasing cohesion (via a decrease in roughness or an increase in RH) results in a decrease in the slope of Dp* vs. u in the packed state-such that a statistically significant increase in u mf /u mf,NC is measured between the particles both at dry and humid conditions. Error bars represent 95% confidence intervals, but may be too small to distinguish on the scale of the plot. [Color figure can be viewed at wileyonlinelibrary.com] AIChE Journal

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Flow Rate of Particles through Apertures Obtained from Self-Similar Density and Velocity Profiles

Cited by 179 publications

References 23 publications

Influence of the gravity on the discharge of a silo

Influence of the gravity on the discharge of a silo

Role of particle size in the kinematic properties of silo flow

How nano‐scale roughness impacts the flow of grains influenced by capillary cohesion

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