Flow and jamming of granular suspensions in foams

Haffner, Benjamin; Khidas, Yacine; Pitois, Olivier

doi:10.1039/c4sm00049h

Cited by 39 publications

(52 citation statements)

References 28 publications

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“…In particular the ratio of the size of the particles to the size of the Plateau borders l is critical to determining how drainage proceeds. This ratio was named confinement parameter by O. Pitois and colleagues [14][15][16]30], and is a key parameter to know whether the particle suspension or the pure liquid flows. l is defined as:…”

Section: Drainage Of Aqueous Foamsmentioning

confidence: 99%

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Foamed emulsion drainage: flow and trapping of drops

et al. 2017

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: Foamed emulsions are ubiquitous in our daily life but the ageing of such systems is still poorly understood. In this study we investigate foam drainage and measure the evolution of the gas, liquid and oil volume fractions inside the foam. We evidence three regimes of ageing. During an initial period of fast drainage, both bubbles and drops are very mobile. As the foam stabilises drainage proceeds leading to a gradual decrease of the liquid fraction and slowing down of drainage. Clusters of oil drops are less sheared, their dynamic viscosity increases and drainage slows down even further, until the drops become blocked. At this point the oil fraction starts to increase in the continuous phase. The foam ageing leads to an increase of the capillary pressure until the oil acts as an antifoaming agent and the foam collapses.

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Section: Drainage Of Aqueous Foamsmentioning

confidence: 99%

“…There exists a number of studies, where foam drainage is studied in the presence of solid particles. In the case of solid particles, Pitois and co-workers have also shown that how the drainage proceeds depends strongly on the ratio of the particle size to the foam channel size [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Foamed emulsion drainage: flow and trapping of drops

et al. 2017

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“…For example, the foam regime transition in aqueous foams is usually caused by a change in the surface viscosity or interface mobility [186,187]. However, it is difficult to make the same claim in foams containing nanoparticles because the presence of hydrophilic solid particles can change the interfacial properties to only a small extent [180].To explain the foam drainage behaviors in the presence of hydrophilic particles, several mechanisms have been proposed, such as rheology of the powder suspension and clogging in the confined regions of the Plateau borders [172,178,181,[183][184][185]. Among them, the most important parameter controlling the drainage behaviors of foams with hydrophilic particles is the confinement parameter, , which relates the size of the particle to the maximum diameter of the circle inscribed in the Plateau border cross-section.…”

mentioning

confidence: 99%

“…To explain the foam drainage behaviors in the presence of hydrophilic particles, several mechanisms have been proposed, such as rheology of the powder suspension and clogging in the confined regions of the Plateau borders [172,178,181,[183][184][185]. Among them, the most important parameter controlling the drainage behaviors of foams with hydrophilic particles is the confinement parameter, , which relates the size of the particle to the maximum diameter of the circle inscribed in the Plateau border cross-section.…”

mentioning

confidence: 99%

“…Among them, the most important parameter controlling the drainage behaviors of foams with hydrophilic particles is the confinement parameter, , which relates the size of the particle to the maximum diameter of the circle inscribed in the Plateau border cross-section. For , particles are trapped in the foams, and the resulting drainage velocity is severely reduced [183][184][185].  The effects of solid particles on the stress state of the gas-liquid interface of foams remain poorly understood.…”

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Effects of reagents and solid particles on drainage and stability of liquid film, foam and froth

Wang¹

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The objective of this study is to explore the interrelated mechanisms governing foam drainage and stability by modeling the foam column kinetics, measuring the interfacial properties of the air-water interface and conducting forced drainage experiments. Studies on foams are usually divided into four length scales: (i) a gasliquid interface (molecular scale), (ii) a liquid film (nanometer scale), (iii) a bubble (millimeter scale), and (iv) a foam (meter scale). Although much progress has been made in each length scale, the correlation between the different length scales remains poorly understood and quantified. The present study seeks to address this problem. In many industrial processes, such as froth flotation and foam fractionation, careful control of the foam or froth stability is required to optimize the process performance. Therefore, an understanding of the correlation between the different length scales is of paramount interest for industrial applications. The present study can be divided into three different parts: (1) foam column kinetics, (2) mechanisms governing foamability and foam stability, and (3) foam drainage in the presence of solid particles.The first part models foam column kinetics to predict the evolution of foam growth, liquid fraction, the transport of liquid and gas in growing foams and foam collapse by analogy with chemical kinetics. First, a modeling framework was formulated to categorize the foam or froth growth models into zeroth, first and second order, according to the dependence of the foam collapse rate on the foam volume or height.Then, a novel kinetic model was developed based on the mass balance of gas and liquid in the foam column to simulate the foam column kinetics. Finally, the simulation results were compared with the reported experimental data. Good agreement between model predictions and published experimental results confirms the validity of the analogy between foam column kinetics and reaction kinetics.Mechanisms governing the foamability and foam stability are crucial to understanding foam behaviors. The foamability and foam stability of surfactant blend and surfactant solutions in different electrolyte concentrations were examined to elucidate the different mechanisms that collectively determine foamability and foam stability. The foam growth kinetic model developed in the previous section was also applied here. First, the foamability of sodium dodecyl sulfate (SDS)-dodecanol (DOH) IIsolutions was investigated to test the conventional theories that apply to a single surfactant of pre-critical micelle concentration (CMC). The remarkable decrease in the foamability of SDS solutions caused by the addition of DOH could not be easily explained by the theories of surface tension and surface viscoelasticity. Instead, alternative mechanisms were proposed. Second, findings regarding the foamability of SDS-DOH solutions were extended to froth flotation, that is, the effect of a nonpolar collector (diesel oil) on the foamability of frother solutions (methyl isobutyl ca...

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Novel Oil‐in‐Water Emulsions Stabilised by Ionic Surfactant and Similarly Charged Nanoparticles at Very Low Concentrations

Jiang

Pei

et al. 2018

Angewandte Chemie

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Novel oil-in-water (O/W) emulsions are prepared which are stabilised by ac ationic surfactant in combination with similarly charged alumina nanoparticles at concentrations as low as 10 À5 m and 10 À4 wt %, respectively.T he surfactant molecules adsorb at the oil-water interface to reduce the interfacial tension and endowd roplets with charge ensuring electrical repulsion between them, whereas the charged particles are dispersed in the aqueous films between droplets retaining thickl amellae,r educing water drainage and hindering flocculation and coalescence of droplets.This stabilization mechanism is universal as it occurs with different oils (alkanes, aromatic hydrocarbons and triglycerides) and in mixtures of anionic surfactant and negatively charged nanoparticles. Further,s uch emulsions can be switched between stable and unstable by addition of an equimolar amount of oppositely charged surfactant whichf orms ion pairs with the original surfactant destroying the repulsion between droplets.

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Flow and jamming of granular suspensions in foams

Cited by 39 publications

References 28 publications

Foamed emulsion drainage: flow and trapping of drops

Foamed emulsion drainage: flow and trapping of drops

Effects of reagents and solid particles on drainage and stability of liquid film, foam and froth

Novel Oil‐in‐Water Emulsions Stabilised by Ionic Surfactant and Similarly Charged Nanoparticles at Very Low Concentrations

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