Mixing particle softness in a two-dimensional hopper: Particle rigidity and friction enable variable arch geometry to cause clogging

Alborzi, Saeed; Abrahamyan, David; Hashmi, Sara M.

doi:10.1103/physreve.107.024901

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…In systems with discrete variables, clogging probabilities are assessed by collecting data over a range of geometric parameters, varying either w c and/or d p in separate experiments. Then, clogging probability refers to the number of clogs that occur divided by the total number of experiments performed 45,46 .…”

Section: Probability Of Cloggingmentioning

confidence: 99%

Pressure-controlled formation of discontinuous clogs in tapered microchannels

Majekodunmi,

Hashmi

2024

Preprint

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In suspension flows through microchannels with parallel walls, rigid particles form clogs that grow continuously in the upstream direction. However, introducing a slight taper to channel walls leads to a qualitatively different clogging mechanism. Clogs of rigid particles do not grow continuously in these tapered pores. Instead, new clogs form upstream of pre-existing clogs, truncating their growth, and thereby creating multiple distinct clogs within a channel. We refer to this novel phenomenon as discontinuous clogging. Here, we investigate its features by analyzing the dimensions and locations of discontinuous clogs in parallel tapered pores. Measurements reveal the discontinuity of clog growth depends strongly on flow driving pressure and particle volume fraction. Increasing volume fraction increases clogging frequency and positions the clogs upstream, in wider regions of the channels. Two regimes of driving pressure appear to exist as the discontinuous clogs are observed to become dramatically longer above a critical pressure. Interestingly, these long clogs are located downstream, towards the channel outlet, at the lowest volume fraction. However, they are increasingly located upstream as volume fraction increases. The dependence of clog location on pressure and volume fraction lends insight into bridging mechanism. Particles arriving simultaneously to a given location can span the channel width to form a bridge, which happens easily at higher volume fractions. Permanent clogs form when driving pressure is lower than the force the bridges can sustain. As driving pressure increases, however, it can overcome the force chains, preventing formation of new permanent clogs, and pushing particles further downstream.

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Section: Probability Of Cloggingmentioning

confidence: 99%

Pressure-controlled formation of discontinuous clogs in tapered microchannels

Majekodunmi,

Hashmi

2024

Preprint

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Particle transport during asymmetric net-zero cyclic fluid flow: Flow in tubes and radial flow in fractures

Hafez,

Santamarina

2024

Powder Technology

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Discontinuous clogging in gently tapered microchannels reveals a transient Markov process

Majekodunmi,

Hashmi

2023

Physics of Fluids

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Colloidal clogging is typically studied in pores with constrictions arranged in parallel or series. In these systems, clogging statistics are governed by Poisson processes; the time interval between clogging events exhibits an exponential distribution. However, an entirely different phenomenon is observed in a gently tapered pore geometry. Unlike in non-tapered constrictions, rigid particles clogging tapered microchannels form discrete and discontinuous clogs. In a parallelized system of tapered microchannels, we analyze distributions of clog dimensions for different flow conditions. Clog width distributions reveal a lognormal process, arising from concurrent clogging across independent parallel microchannels. Clog lengths, however, which are analogous to growth time, are exponentially distributed. This indicates a Poisson process where events do not occur simultaneously. These two processes are contradictory: clogging events are statistically dependent within each channel, while clogs grow simultaneously across independent channels. The coexistence of Poisson and lognormal processes suggests a transient Markov process in which clogs occur both independently of, and dependently on, other clogs. Therefore, discussions of the stochastic character of clogging may require holistic consideration of the quantities used to assess it. This study reveals small adjustments to pore spaces can lead to qualitative differences in clogging dynamics, suggesting the importance of geometry.

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Mixing particle softness in a two-dimensional hopper: Particle rigidity and friction enable variable arch geometry to cause clogging

Cited by 4 publications

References 41 publications

Pressure-controlled formation of discontinuous clogs in tapered microchannels

Pressure-controlled formation of discontinuous clogs in tapered microchannels

Particle transport during asymmetric net-zero cyclic fluid flow: Flow in tubes and radial flow in fractures

Discontinuous clogging in gently tapered microchannels reveals a transient Markov process

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