Microbubble generation in a co-flow device operated in a new regime

Castro-Hernández, Elena; Hoeve, Wim van; Lohse, Detlef; Gordillo, José Manuel

doi:10.1039/c0lc00731e

Cited by 128 publications

(144 citation statements)

References 57 publications

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“…This geometry-controlled regime was observed at lower gas pressures (P  41.3 kPa) or liquid flow rates (Q l  58 L/min). At higher gas pressures (P > 41.3 kPa) and liquid flow rates (Q l > 58 L/min), [196] a flow-controlled regime was observed. In this regime, the gas thread width was less than the width of the nozzle, was located in the center of the nozzle, and stayed downstream of the nozzle.…”

Section: Microbubble Generation Regimesmentioning

confidence: 99%

“…Regarding size, Gañ á n-Calvo et al [205], [207] [196] derived a scaling law for 2-D co-flow devices with a square cross-section nozzle that was similar to Equation 7-3 except the exponent was 5/12 (flow conditions were: Re  100; We  1, and Q g /Q l < 0.03). Garstecki et al [208], [211] reported a different scaling law for the volume of a MB produced in a shortchannel nozzle FFMD with rectangular cross-section…”

Section: Introductionmentioning

confidence: 99%

“…Garstecki et al [210] In this chapter, 2-D expanding-nozzle FFMDs were fabricated and MB diameter and production rates were measured over a range of gas pressures and liquid flow rates. In order to facilitate comparison with previous work, Tween -a surfactant and widely used shell material [196], [208]- [210] -was used to stabilize the MBs. A relationship between MB production rate and diameter as a function of input parameters was subsequently developed.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike agitation methods, microfluidic devices produce microbubbles one at a time in a serial process, allowing production rates and diameters to be measured directly using high speed video microscopy [195], [196]. Alternatively, a Coulter counter can be used to determine MB size distribution and concentration after production.…”

Section: Introductionmentioning

confidence: 99%

“…We  1, and Q g /Q l < 0.03, where Q g is gas flow rate) [196]. For FFMDs with a short- [208], [211] showed that the time that the gas thread stayed open at the nozzle (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative Ultrasound Molecular Imaging in Large Blood Vessel Environments

Wang

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Stroke is the fourth leading cause of death in the United States. The current standard of care for carotid atherosclerosis addresses the disease after the plaque has developed to the point at which it is detectable using anatomical-based imaging to measure luminal stenosis. Ultrasound molecular imaging, possessing the ability to image the molecular signature of early vascular inflammation, potentially decades prior to the formation of plaque, may enable more timely diagnosis and treatment of atherosclerosis and atherosclerotic risk. Additionally, it simultaneously meets the needs for rapid, lowcost, and radiation-free molecular marker detection that may facilitate clinical adoption. Unfortunately, existing ultrasound-based molecular imaging is limited to small blood vessel environments, and unable to measure molecular marker concentration in large blood vessels.In the first part of the dissertation, the design, implementation, and validation of a In the second part of the dissertation, the characterization of an expanding-nozzle flow-focusing microfluidic device for the generation of monodisperse microbubbles is ii presented. Significantly, the characterization could facilitate real-time adjustment of microbubble diameter and production rate using microfluidic devices.iii

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Section: Microbubble Generation Regimesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…We  1, and Q g /Q l < 0.03, where Q g is gas flow rate) [196]. For FFMDs with a short- [208], [211] showed that the time that the gas thread stayed open at the nozzle (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative Ultrasound Molecular Imaging in Large Blood Vessel Environments

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Microdroplet coalescences at microchannel junctions with different collision angles

Wang

Lü

et al. 2012

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com).Microdroplet coalescence mechanism is very important for the miniaturization of multiphase chemical processes with microstructured devices. Using three working systems with different physical properties, this article presents an experimental study on the fluid dynamics of microdroplet coalescence at different microchannel junctions. The critical capillary number to distinguish coalescence or noncoalescence of microdroplet is investigated and its variations with droplet size, collision angle, and physical properties are analyzed with two important parameters -the film drainage time and droplet contact time. Experimental results indicate that microdroplet coalescence can be enhanced by reducing the droplet collision angle. The differences of microdroplet coalescences in confined microchannels and free-flowing spaces are provided with the analysis of critical capillary number. A model equation is proposed to predict the critical capillary numbers in this study, which may provide valuable information for the design and development of new microstructured chemical device.

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Dynamic formation and scaling law of hollow droplet with gas/oil/water system in dual‐coaxial microfluidic devices

et al. 2017

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in Wiley Online Library (wileyonlinelibrary.com)Based on the one-step microfluidic method of producing hollow droplet with thin film, this article studies the effect of water and oil flow rate, gas pressure, and viscosity of aqueous phase on the dynamic formation and size of hollow droplet by analyzing large amounts of data acquired automatically. The results show that the filling stage of hollow droplet is similar to that of microbubble formation, while the necking stage is similar to that of droplet formation process. Furthermore, based on the data and mathematical model describing droplet formation mechanism, a filling stage model including Capillary number of continuous phase is developed. Considering the dynamic interface breakup and displacement of droplet in necking stage, a necking stage model is developed. The results show that the model results considering filling and necking stage fit well with the experimental data, and the relative error is less than 5%. Finally, the same model with parameters is used to predict the size of hollow droplet with other systems and devices, and the model is proved to be relative precise in our experimental conditions. The results presented in this work provide a more indepth understanding of the dynamic formation and scaling law of hollow droplet with G/L/L systems in microfluidic devices.(a) Setting the same inlet pressure p g , Q g is nearly constant varying other parameters in this work, such as Q w and Q o . (b) Volumetric flow rate is in linear correlation with gas inlet pressure statistically. [Color figure can be viewed at wileyonlinelibrary.com]

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Microbubble generation in a co-flow device operated in a new regime

Cited by 128 publications

References 57 publications

Quantitative Ultrasound Molecular Imaging in Large Blood Vessel Environments

Quantitative Ultrasound Molecular Imaging in Large Blood Vessel Environments

Microdroplet coalescences at microchannel junctions with different collision angles

Dynamic formation and scaling law of hollow droplet with gas/oil/water system in dual‐coaxial microfluidic devices

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