High‐frequency formation of bubble with short length in a capillary embedded step T‐junction microdevice

Sheng, Lin; Chen, Yuchao; Deng, Jian; Luo, Guangsheng

doi:10.1002/aic.17376

Cited by 25 publications

(50 citation statements)

References 42 publications

(76 reference statements)

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“…The origin of the Y -axis and Z -axis is the center of the microchannel (see the gray dashed line in Figure ). The bubble’s three-dimensional morphology is realized through the two-dimensional plane, which rotates 360° with the X -axis as the bus line. , Thus, the Taylor bubble is approximatively composed of many disks along the X -axis, and the height of each disk is fixed at 1 pixel (equals 2.35 μm).…”

Section: Resultsmentioning

confidence: 99%

Hydrodynamics and Scaling Laws of Gas–Liquid Taylor Flow in Viscous Liquids in a Microchannel

Sheng

Chang

Deng

et al. 2022

Ind. Eng. Chem. Res.

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The hydrodynamics of gas–liquid Taylor flow in microchannels is vital to the microreactor’s application, but its characteristics in viscous liquids are rarely reported. Accordingly, this study concentrates on the characteristics of bubble behavior in viscous liquids (45.6–240.5 mPa·s). The results show that the viscosity effect could dominate the bubble morphology. Importantly, considering the liquid film distribution, a novel parameter as the equivalent liquid film thickness is proposed for the square microchannel and it is strongly related to the capillary number and gas–liquid flow rate ratio. Besides, the bubble velocity first decreases to a minimum value and then becomes faster with the flow rate of the liquid, and the ideality of the multiphase system decreases with the increase of liquid viscosity and pressure drop. Finally, the viscosity term is introduced to the pressure drop equation based on the Lockhart–Martinelli type. This work enriches the understanding of the viscosity effect on gas–liquid microflows.

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Section: Resultsmentioning

confidence: 99%

Hydrodynamics and Scaling Laws of Gas–Liquid Taylor Flow in Viscous Liquids in a Microchannel

Sheng

Chang

Deng

et al. 2022

Ind. Eng. Chem. Res.

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“…The two phases were met at a microfluidic T-junction ( W × H : 400 × 400 μm). The downstream length of the T-junction is 15 cm, and the microdevice fabrication method is the same as our previous work . The generation dynamics of the Taylor bubble were captured through a digital high-speed camera (Olympus, i-SPEED TR, Japan), and the recording frame rate was fixed at 2000 fps in all the experiments.…”

Section: Experimental Methods and Materialsmentioning

confidence: 99%

Taylor Bubble Generation Rules in Liquids with a Higher Viscosity in a T-Junction Microchannel

Sheng

Chang

Deng

et al. 2022

Ind. Eng. Chem. Res.

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Generation of bubbles in a T-junction microdevice is vital to microfluidic applications for its advantages of easy fabrication and scaling-up, but the bubble generation in liquids with a higher viscosity in the T-junction is rarely reported for the unstable dispersion behavior under the constant flow rate-driven condition. Accordingly, this work investigates the bubble generation rules in liquids with a higher viscosity (45.6−240.5 mPa•s) under the constant-pressure method. It shows that the bubble formation process in higher viscous liquids contains three stages, expansion, shrinking, and necking, which are obviously different from the filling and squeezing stages in the lower viscous liquid. Importantly, the generation of satellite bubbles as a new bubble generation performance could be observed for the first time in the gas−liquid microdispersion process. The new dispersion mechanism and some novel phenomena are revealed by the interface evolution rules. Finally, a novel mathematical model is developed to predict the bubble length.

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“…The root cause of these differences was that the droplets had different force balance conditions in different microfluidic constrictions 24–28 . This could be strongly verified by the researches on the interface rupture of droplet and bubble in the microfluidic T‐junction, which showed that a small variation in the structure of the T‐junction would result in the changes of the size regulation law of the droplet and bubble generated 29–34 . It had been widely demonstrated that the size of the droplet and bubble generated in the T‐junction depended mainly on the interface breakup mechanism, that is, the force balance conditions 35–38 .…”

Section: Introductionmentioning

confidence: 94%

Droplet breakup in the square microchannel with a short square constriction to generate slug flow

Wang

Liu

et al. 2022

AIChE Journal

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Droplet breakup in microconstrictions is an important phenomenon in industrial applications. This work aimed to investigate the droplet breakup in the square microchannel with a short square constriction to generate the slug flow, which drew little attention before. Mechanism analysis indicated that this breakup process included the shear-force-dominated, squeezing-force-dominated, and pinch-off stages. Nonuniform daughter droplets were generated in the constriction with their interface restricted in the horizontal and perpendicular directions by the microchannel walls.The average relative deviation of the daughter droplet size was <30%, much lower than that for the breakup with the daughter droplet restricted only in one direction.An empirical equation with a deviation of <20% was provided to show the dependence of the daughter droplet size on the operation conditions. The comparison results suggested that the different restriction effects of microchannel wall on daughter droplets led to the different breakup mechanisms in different constrictions.

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High‐frequency formation of bubble with short length in a capillary embedded step T‐junction microdevice

Cited by 25 publications

References 42 publications

Hydrodynamics and Scaling Laws of Gas–Liquid Taylor Flow in Viscous Liquids in a Microchannel

Hydrodynamics and Scaling Laws of Gas–Liquid Taylor Flow in Viscous Liquids in a Microchannel

Taylor Bubble Generation Rules in Liquids with a Higher Viscosity in a T-Junction Microchannel

Droplet breakup in the square microchannel with a short square constriction to generate slug flow

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