Coalescence map for bubbles in surfactant-free aqueous electrolyte solutions

Horn, Roger G.; Castillo, Lorena A. Del; Ohnishi, Satomi

doi:10.1016/j.cis.2011.05.006

Cited by 65 publications

(45 citation statements)

References 38 publications

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“…When the film thickness reduces to about 100 nm, Van der Waals attraction will accelerate the drainage process (Almatroushi and Borhan 2006). Once the liquid film is thinning less than a critical thickness (a few tens of nanometers) (Horn et al 2011), film rupture occurs instantaneously leading to the bubble coalescence as the third stage. Following bubble fusion process, the surface of coalesced bubble shows strong oscillations due to the release of surface energy.…”

Section: Resultsmentioning

confidence: 99%

Experimental study of microbubble coalescence in a T-junction microfluidic device

Wang

Tan

et al. 2011

Microfluid Nanofluid

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This study presents the microbubble coalescence process in a confined microchannel. Triple T-junction microfluidic devices with different main channel size were designed to generate monodispersed microbubble pairs with air/n-butyl alcohol-glycerol solution as the working system. The head-on collision of microbubble pair was realized in the microfluidic devices. Three collision results including absolute coalescence, probabilistic coalescence, and noncoalescence were distinguished. The effects of liquid viscosities and two-phase superficial velocities on the coalescence behavior were determined. The results showed that microbubble coalescence process in the confined space was slightly faster than in the free space. Increasing liquid viscosity apparently prevents coalescence. In the probabilistic coalescence region, higher two-phase superficial velocity could reduce the percentage of coalescence events. Two characteristic parameters representing the bubble contact time and film drainage time have been introduced to analyze the microbubble coalescence behaviors and a linear correlation could clearly distinguish the coalescence and noncoalescence region.

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Section: Resultsmentioning

confidence: 99%

Experimental study of microbubble coalescence in a T-junction microfluidic device

Wang

Tan

et al. 2011

Microfluid Nanofluid

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“…In the case of mobile surfaces the velocity profile is uniform (the plug flow), unlike the immobile surfaces with the velocity profile having a parabolic shape (the Poiseuille flow). The latter case is associated with a large hydrodynamic resistance which retards the drainage rate and enhances the film stability [5]. The rapid coalescence of bubbles in pure DI water is ascribed to the mobile air-water interface of a liquid film between two bubbles [73].…”

Section: Surface Rheologymentioning

confidence: 99%

“…Monitoring the coalescence of a single rising bubble to a free surface has been considered as another variation of this technique [5]. The air above the water surface can be considered to represent a bubble with infinite radius.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Depending on the balance of the capillary pressure and disjoining pressures, if the film drainage takes longer than the bubbles' contact time, the liquid film is considered to be stable, and coalescence does not take place. Otherwise the liquid film between bubbles ruptures at a critical thickness within the range of 200-10 nm, depending on the concentration of chemicals (surfactants or salts), surface impurities and bubble approach speed [5,6]. Salts and surfactants influence bubble coalescence by changing the intermolecular forces and surface rheology of liquid films between bubbles.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…Decreasing hydrophobic interactions [66][67][68], influencing the properties of air-solution interfaces such as surface tension and viscosity [25,60], affecting drainage and rupture of thin liquid films by migration of dissolved gases in the solution [5,25,60] are a number of explanations have been proposed to link the solubility of gas molecules to bubble coalescence in salt solutions.…”

Section: Gas Solubilitymentioning

confidence: 99%

See 2 more Smart Citations

A quantitative review of the transition salt concentration for inhibiting bubble coalescence

Firouzi

Howes

Nguyen

2015

Advances in Colloid and Interface Science

113

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Some salts have been proven to inhibit bubble coalescence above a certain concentration called the transition concentration. The transition concentration of salts has been investigated and determined by using different techniques. Different mechanisms have also been proposed to explain the stabilising effect of salts on bubble coalescence. However, as yet there is no consensus on a mechanism which can explain the stabilizing effect of all inhibiting salts. This paper critically reviews the experimental techniques and mechanisms for the coalescence of bubbles in saline solutions. The transition concentrations of NaCl, as the most popularly used salt, determined by using different techniques such as bubble swarm, bubble pairs, thin liquid film micro-interferometry were analysed and compared. For a consistent comparison, the concept of TC95 was defined as a salt concentration at which the -percentage coalescence‖ of bubbles reduces by 95% relative to the highest (100% in pure water) and lowest (in high-salt concentration) levels. The results show a linear relationship between the TC95 of NaCl and the reciprocal of the square root of the bubble radius. This relationship holds despite different experimental techniques, salt purities and bubble approach speeds, and highlights the importance of the bubble size in bubble coalescence. The available theoretical models for inhibiting effect of salts have also been reviewed. The failure of these models in predicting the salt transition concentration commands further theoretical development for a better understanding of bubble coalescence in salt solutions.

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On the role of the macroscopic deformation in liquid film drainage between bubbles

Song

Zhang

et al. 2023

AIChE Journal

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The collision of bubbles in multiphase reactors is critical to bubble size distribution. However, the theoretical models that can reasonably predict collision outcomes and the experimental data that can be used to directly verify the models are still very lacking. We studied the collision of two bubbles in clean water through experiments and theoretical modeling, revealing the mechanism that the collision result shifts from coalescence to rebound with increasing collision velocity. The macroscopic deformation (MacrD) of bubbles is associated with the film drainage via a segmented linear equation as a function of the film radius and initial Weber number. Thus, the current model can reflect the effect of MacrD in a self‐consistent way. The coalescence times and critical coalescence velocities predicted by the model were in good agreement with the experiments. This work provides novel insights into bubble coalescence modeling and serves to improve the accuracy of reactor simulations.

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Coalescence map for bubbles in surfactant-free aqueous electrolyte solutions

Cited by 65 publications

References 38 publications

Experimental study of microbubble coalescence in a T-junction microfluidic device

Experimental study of microbubble coalescence in a T-junction microfluidic device

A quantitative review of the transition salt concentration for inhibiting bubble coalescence

On the role of the macroscopic deformation in liquid film drainage between bubbles

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