Bubble breakup with permanent obstruction in an asymmetric microfluidic <scp>T</scp>‐junction

Wang, Xiaoda; Zhu, Chunying; Fu, Taotao

doi:10.1002/aic.14704

Cited by 39 publications

(23 citation statements)

References 48 publications

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“…Similar phenomenon was observed by Lu et al [12] for a bubble passing through the T junction. For bubble breakup at asymmetric microfluidic Tjunction, Wang et al [13] experimentally found that this process can be divided into three stages: squeezing, transition, and pinch-off stages. The evolution of the minimum width of the bubble neck with the remaining time before the breakup can be scaled by a power-law relationship.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of partially obstructed breakup of bubbles in microfluidic Y‐junctions

Zhao

Zhu

et al. 2018

Electrophoresis

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For revealing the dynamics of partially obstructed breakup of bubbles in microfluidic Y-junctions, the combination of dimensionless power-law and geometric model was applied to study the effects of capillary number, bubble length, and channel angle on the bubble rupture process. In the squeezing process, the gas-liquid interface curve follows the parabolic model. For the evolution of the bubble neck during breakup, the increase of the bubble length, the channel angle, and the capillary number leads to the decrease of the focus distance α. The chord m increases with the increase of the capillary number and the decrease of the bubble length, and it would reach the maximum value when the channel angle is 90°. In the fast pinch-off stage during bubble breakup, the bubble's neck curve no longer conforms to the parabolic model so the focus and chord no longer exist. For the evolution of the bubble head during breakup, the value of γ approaches 1 with the increase of the capillary number and the bubble length, and with the close of the channel angle to 90°. It is found that the quadrilateral model can be applied for the partially obstructed rupture of bubbles in the symmetrical microfluidic Y-junction.

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Section: Introductionmentioning

confidence: 99%

Dynamics of partially obstructed breakup of bubbles in microfluidic Y‐junctions

Zhao

Zhu

et al. 2018

Electrophoresis

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“…At the critical time, the curvature at the stagnation point becomes the largest, which can easily lead to the spontaneous breakup of the bubble according to the surface‐tension‐driven mechanism proposed by Hoang et al This mechanism suggests that the surface tension induces significant reverse flow to the stagnant point, which quickens the breakup. Besides, Wang et al suggested that when the bubble neck is thin enough, the circulation flow around the bubble neck would also aggravate the Raleigh‐Plateau instability and the bubble breakup. The critical neck thickness in the case shown in Figure is found as δ c / w = 0.26 (i.e., =1– ω c / w ), which is in accordance with the literature .…”

Section: Resultsmentioning

confidence: 99%

“…Besides, Wang et al suggested that when the bubble neck is thin enough, the circulation flow around the bubble neck would also aggravate the Raleigh‐Plateau instability and the bubble breakup. The critical neck thickness in the case shown in Figure is found as δ c / w = 0.26 (i.e., =1– ω c / w ), which is in accordance with the literature . Afterwards, the bubble neck shrinks and the water contracts from the two sides dramatically (indicated by the rapid decrease of L l and L r , and increase of ω ) till the bubble ruptures ( t = t b ).…”

Section: Resultsmentioning

confidence: 99%

“…Also through a 2‐D model, Leshansky et al showed that in the surface tension‐dominated system, the breakup time was negatively associated with the flow rate and Ca number. However, this model failed to predict both the numerical and experimental results in 3‐D systems . Hoang et al ascribed this discrepancy to a 3‐D capillary effect driven by the larger surface tension at the stagnation point.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Bubble splitting under gas–liquid–liquid three‐phase flow in a double T‐junction microchannel

Liu

Yue²,

Zhao

et al. 2017

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com)Gas-aqueous liquid-oil three-phase flow was generated in a microchannel with a double T-junction. Under the squeezing of the dispersed aqueous phase at the second T-junction (T2), the splitting of bubbles generated from the first T-junction (T1) was investigated. During the bubble splitting process, the upstream gas-oil two-phase flow and the aqueous phase flow at T2 fluctuate in opposite phases, resulting in either independent or synchronous relationship between the instantaneous downstream and upstream bubble velocities depending on the operating conditions. Compared with two-phase flow, the modified capillary number and the ratio of the upstream velocity to the aqueous phase velocity were introduced to predict the bubble breakup time. The critical bubble breakup length and size laws of daughter bubbles/slugs were thereby proposed. These results provide an important guideline for designing microchannel structures for a precise manipulation of gas-liquid-liquid three-phase flow which finds potential applications among others in chemical synthesis.

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“…[7] In addition, computational fluid dynamics (CFD) has been more and more prevalent with the improvement of computing capacity since it provides detailed fundamentals of gas-solid hydrodynamics. Simulations based on CFD have been reported by numerous studies, [8][9][10][11][12][13] in which the two-fluid model (TFM) is found promising in predicting hydrodynamics of BFBs with coarse particles (i.e. Geldart's A or B type particles).…”

mentioning

confidence: 99%

Simulation of bubbling fluidized beds with cohesive particles by incorporating a novel structure‐Based drag model into the two‐fluid model

Luo

Zheng

et al. 2017

Can J Chem Eng

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A novel structure‐based drag model was proposed to study the hydrodynamics of bubbling fluidized beds (BFBs) operated with ultrafine cohesive particles by considering local heterogeneous flow structures. Firstly, a local structure parameters model capturing the internal flow structures of the studied system was built by balance equations and empirical formulas and the solutions (i.e. local structure parameters) of this model solved by global search algorithm were evaluated in terms of hydrodynamics, energy consumption, and voidage. Then the local structure parameters were employed to derive the structure‐based drag model. Lastly, three drag models (i.e. the structure‐based drag model, Gidaspow model, and Syamlal‐O'Brien model) were investigated and incorporated separately into the two‐fluid model, where the simulation results were also separately compared with available experimental data. The comparison shows that Gidaspow and Syamlal‐O'Brien drag models failed to predict the solid volume fraction profiles. However, the error analysis results of the structure‐based drag model indicate the average absolute relative error of solid volume fraction in the radial direction is 7.04 % and 5.64 % at the height of 0.1 m and 0.2 m respectively, which exhibits promising predictions. Thus, it is feasible to simulate the BFBs with cohesive particles through the combination of the structure‐based drag model with the two‐fluid model.

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Bubble breakup with permanent obstruction in an asymmetric microfluidic T‐junction

Cited by 39 publications

References 48 publications

Dynamics of partially obstructed breakup of bubbles in microfluidic Y‐junctions

Dynamics of partially obstructed breakup of bubbles in microfluidic Y‐junctions

Bubble splitting under gas–liquid–liquid three‐phase flow in a double T‐junction microchannel

Simulation of bubbling fluidized beds with cohesive particles by incorporating a novel structure‐Based drag model into the two‐fluid model

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