Study of flow behaviors of droplet merging and splitting in microchannels using Micro-PIV measurement

Shen, Feng; Li, Yang; Liu, Zhaomiao; Li, Xiu Jun

doi:10.1007/s10404-017-1902-y

Cited by 34 publications

(14 citation statements)

References 96 publications

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“…Despite significant progress on velocity field measurements in small channels using particle image velocimetry (PIV) techniques [19][20][21][22], concentration profiles are less well investigated. Mixing patterns have been obtained from the measurement of fluorescence intensity of passive scalars with micro Laser Induced Fluorescence (micro-LIF) [23,24].…”

Section: Introductionmentioning

confidence: 99%

Studies on mass transfer of europium(III) in micro-channels using a micro Laser Induced Fluorescence technique

Angeli

Tsaoulidis

Weheliye

2019

Chemical Engineering Journal

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The mass transfer of europium(III) from an aqueous to an organic phase was studied in a quartz microchannel (internal diameter of 200 μm) using a novel micro Laser Induced Fluorescence (micro-LIF) technique. Europium(III) was extracted from a 1M nitric acid solution into an organic solution of TBP(1.2M)/CMPO(0.2M) in Exxsol D80. For the flow rates investigated plug flow was established. An experimental and data processing methodology was developed to calculate concentration profiles from the fluorescing light intensity profiles in both phases at different locations along the microchannel. In particular, the effect that the high light intensity of the organic phase has on the measurements in the aqueous phase was taken into account. Mass transfer was found to be significant in the beginning of the channel close to the inlet (1 mm distance) with extraction percentages varying between 20 to 40% depending on the total flow rate. High extraction efficiency (~80%) was achieved at short residence times (in the first 6 s), while the overall volumetric mass transfer coefficients varied between 0.05 and 3.3 s-1 .

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Section: Introductionmentioning

confidence: 99%

Studies on mass transfer of europium(III) in micro-channels using a micro Laser Induced Fluorescence technique

Angeli

Tsaoulidis

Weheliye

2019

Chemical Engineering Journal

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“…While in the divergent channel geometry, as the droplet merges, a strong vortex motion is generated, resulting in the rear droplet enveloping the front droplets. Shen, Li [31] investigated fundamental flow characteristics of a water-ethanol droplet suspended in sunflower oil merging in the T-junction channel and rectangular microgroove, and splitting in two different microstructures, i.e., cylinder obstruction and Y-junction bifurcation via micro-PIV technique. The microgroove generates higher probability for the coalescence of the droplet compared to the T-junction in a microchannel.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Water-in-Oil Droplets in T-Junction Microchannel by Micro-PIV

et al. 2021

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Water-in-oil droplets have huge importance in chemical and biotechnology applications, despite their difficulty being produced in microfluidics. Moreover, existing studies focus more on the different shape of microchannels instead of their size, which is one of the critical factors that can influence flow characteristics of the droplets. Therefore, the present work aims to study the behaviours of water-in-oil droplets at the interfacial surface in an offset T-junction microchannel, having different radiuses, using micro-PIV software. Food-grade palm olein and distilled water seeded with polystyrene microspheres particles were used as working fluids, and their captured images showing their generated droplets’ behaviours focused on the junction of the respective microfluidic channel, i.e., radiuses of 400 µm, 500 µm, 750 µm and 1000 µm, were analysed via PIVlab. The increasing in the radius of the offset T-junction microchannel leads to the increase in the cross-sectional area and the decrease in the distilled water phase’s velocity. The experimental velocity of the water droplet is in agreement with theoretical values, having a minimal difference as low as 0.004 mm/s for the case of the microchannel with a radius of 750 µm. In summary, a small increase in the channel’s size yields a significant increase in the overall flow of a liquid.

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“…A localised obstruction in a channel may lead to either coalescence of two droplets or break-up of a droplet into smaller parts depending on its positioning and size (Vladisavljević et al 2013). The merging of two droplets can be achieved by smoothly expanding or contracting the micro-fluidic channel (Bremond et al 2008;Seemann et al 2012;Tabeling 2014) and multiple forms of coalescence of two droplets downstream of a sudden channel expansion have been characterised experimentally by Shen et al (2017). Bremond et al (2008) find that two droplets tend to coalesce upon separation occurring after collision.…”

Section: Introductionmentioning

confidence: 99%

Self-assembly of coated microdroplets at the sudden expansion of a microchannel

Schirrmann

Cáceres-Aravena

Juel

2021

Microfluid Nanofluid

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We report observations of the self-assembly of coated droplets into regular clusters at the sudden expansion of a microfluidic channel. A double emulsion consisting of a regular train of coated microdroplets was created upstream of the channel expansion, so that the inter-drop distance, droplet length, velocity and coating thickness could be varied by imposing different inlet pressures, albeit not independently. Provided that the enlarged channel remains sufficiently confined to prohibit propagation in double file, droplets can assemble sequentially into regular linear clusters at the expansion. Droplets join a cluster via the coalescence of their coating film with that of the group ahead. This coalescence occurs when the droplets approach each other to within a critical distance at the expansion, enabled by hydrodynamic interactions within the train. Clusters comprising a finite number of droplets are obtained because reconfiguration of the droplet assembly during coalescence increases the distance to the following droplet. Decreasing the inter-drop distance increases the cluster size up to a maximum value beyond which continuous clusters form. Formalising these observations in a simple model reveals that clusters of any size are possible but that they occur for increasingly narrow ranges of parameter values. Our experimental observations suggests that background experimental fluctuations limit the maximum discrete cluster size in practice. This method of self-assembly offers a robust alternative to flow focusing for encapsulating multiple cores in a single coating film and the potential to build more complex colloidal building blocks by de-confining the clusters.

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Study of flow behaviors of droplet merging and splitting in microchannels using Micro-PIV measurement

Cited by 34 publications

References 96 publications

Studies on mass transfer of europium(III) in micro-channels using a micro Laser Induced Fluorescence technique

Studies on mass transfer of europium(III) in micro-channels using a micro Laser Induced Fluorescence technique

Evolution of Water-in-Oil Droplets in T-Junction Microchannel by Micro-PIV

Self-assembly of coated microdroplets at the sudden expansion of a microchannel

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