Liquid–liquid flows with non-newtonian dispersed phase in a t-junction microchannel

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Liquid–liquid flows with non-newtonian dispersed phase in a t-junction microchannel. / Yagodnitsyna, Anna ; Kovalev, Alexander; Bilsky, Artur.

In: Micromachines, Vol. 12, No. 3, 335, 03.2021.

Research output: Contribution to journal › Article › peer-review

BibTeX

@article{2b2b1fe2663143ad873708e51d232f44,

title = "Liquid–liquid flows with non-newtonian dispersed phase in a t-junction microchannel",

abstract = "Immiscible liquid–liquid flows in microchannels are used extensively in various chemical and biological lab-on-a-chip systems when it is very important to predict the expected flow pattern for a variety of fluids and channel geometries. Commonly, biological and other complex liquids express non-Newtonian properties in a dispersed phase. Features and behavior of such systems are not clear to date. In this paper, immiscible liquid–liquid flow in a T-shaped microchannel was studied by means of high-speed visualization, with an aim to reveal the shear-thinning effect on the flow patterns and slug-flow features. Three shear-thinning and three Newtonian fluids were used as dispersed phases, while Newtonian castor oil was a continuous phase. For the first time, the influence of the non-Newtonian dispersed phase on the transition from segmented to continuous flow is shown and quantitatively described. Flow-pattern maps were constructed using nondimensional complex We0.4·Oh0.6 depicting similarity in the continuous-to-segmented flow transition line. Using available experimental data, the proposed nondimensional complex is shown to be effectively applied for flow-pattern map construction when the continuous phase exhibits non-Newtonian properties as well. The models to evaluate an effective dynamic viscosity of a shear-thinning fluid are discussed. The most appropriate model of average-shear-rate estimation based on bulk velocity was chosen and applied to evaluate an effective dynamic viscosity of a shear-thinning fluid. For a slug flow, it was found that in the case of shear-thinning dispersed phase at low flow rates of both phases, a jetting regime of slug formation was established, leading to a dramatic increase in slug length.",

keywords = "Flow pattern, Liquid, Liquid flow, Microfluidics, Shear-thinning fluid, Slug flow",

author = "Anna Yagodnitsyna and Alexander Kovalev and Artur Bilsky",

year = "2021",

month = mar,

doi = "10.3390/mi12030335",

language = "English",

volume = "12",

journal = "Micromachines",

issn = "2072-666X",

publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",

number = "3",

}

RIS

TY - JOUR

T1 - Liquid–liquid flows with non-newtonian dispersed phase in a t-junction microchannel

AU - Yagodnitsyna, Anna

AU - Kovalev, Alexander

AU - Bilsky, Artur

PY - 2021/3

Y1 - 2021/3

N2 - Immiscible liquid–liquid flows in microchannels are used extensively in various chemical and biological lab-on-a-chip systems when it is very important to predict the expected flow pattern for a variety of fluids and channel geometries. Commonly, biological and other complex liquids express non-Newtonian properties in a dispersed phase. Features and behavior of such systems are not clear to date. In this paper, immiscible liquid–liquid flow in a T-shaped microchannel was studied by means of high-speed visualization, with an aim to reveal the shear-thinning effect on the flow patterns and slug-flow features. Three shear-thinning and three Newtonian fluids were used as dispersed phases, while Newtonian castor oil was a continuous phase. For the first time, the influence of the non-Newtonian dispersed phase on the transition from segmented to continuous flow is shown and quantitatively described. Flow-pattern maps were constructed using nondimensional complex We0.4·Oh0.6 depicting similarity in the continuous-to-segmented flow transition line. Using available experimental data, the proposed nondimensional complex is shown to be effectively applied for flow-pattern map construction when the continuous phase exhibits non-Newtonian properties as well. The models to evaluate an effective dynamic viscosity of a shear-thinning fluid are discussed. The most appropriate model of average-shear-rate estimation based on bulk velocity was chosen and applied to evaluate an effective dynamic viscosity of a shear-thinning fluid. For a slug flow, it was found that in the case of shear-thinning dispersed phase at low flow rates of both phases, a jetting regime of slug formation was established, leading to a dramatic increase in slug length.

AB - Immiscible liquid–liquid flows in microchannels are used extensively in various chemical and biological lab-on-a-chip systems when it is very important to predict the expected flow pattern for a variety of fluids and channel geometries. Commonly, biological and other complex liquids express non-Newtonian properties in a dispersed phase. Features and behavior of such systems are not clear to date. In this paper, immiscible liquid–liquid flow in a T-shaped microchannel was studied by means of high-speed visualization, with an aim to reveal the shear-thinning effect on the flow patterns and slug-flow features. Three shear-thinning and three Newtonian fluids were used as dispersed phases, while Newtonian castor oil was a continuous phase. For the first time, the influence of the non-Newtonian dispersed phase on the transition from segmented to continuous flow is shown and quantitatively described. Flow-pattern maps were constructed using nondimensional complex We0.4·Oh0.6 depicting similarity in the continuous-to-segmented flow transition line. Using available experimental data, the proposed nondimensional complex is shown to be effectively applied for flow-pattern map construction when the continuous phase exhibits non-Newtonian properties as well. The models to evaluate an effective dynamic viscosity of a shear-thinning fluid are discussed. The most appropriate model of average-shear-rate estimation based on bulk velocity was chosen and applied to evaluate an effective dynamic viscosity of a shear-thinning fluid. For a slug flow, it was found that in the case of shear-thinning dispersed phase at low flow rates of both phases, a jetting regime of slug formation was established, leading to a dramatic increase in slug length.

KW - Flow pattern

KW - Liquid

KW - Liquid flow

KW - Microfluidics

KW - Shear-thinning fluid

KW - Slug flow

UR - http://www.scopus.com/inward/record.url?scp=85103486805&partnerID=8YFLogxK

U2 - 10.3390/mi12030335

DO - 10.3390/mi12030335

M3 - Article

C2 - 33809906

AN - SCOPUS:85103486805

VL - 12

JO - Micromachines

JF - Micromachines

SN - 2072-666X

IS - 3

M1 - 335

ER -

ID: 28255963