TY - JOUR

T1 - Flow hydrodynamics of immiscible liquids with low viscosity ratio in a rectangular microchannel with T-junction

AU - Kovalev, Alexander V.

AU - Yagodnitsyna, Anna A.

AU - Bilsky, Artur V.

PY - 2018/11/15

Y1 - 2018/11/15

N2 - We present an experimental study of the liquid-liquid system with extremely low viscosity ratio (10−3) in a T-shaped microchannel with 120 × 120 μm inlets and a 240 × 120 μm outlet channel. Six different flow patterns have been observed: plug, droplet, slug, throat-annular and parallel flow. A specific plug flow pattern was found where micron-sized droplets or even a jet breaks off from the rear meniscus of a plug. In addition to typical Taylor-shaped plugs the dumbbell-like plugs were observed. Flow visualization data were summarized in the flow pattern maps. Plug length and velocity were measured based on flow visualization results. It was found that the plug velocity can be fitted by power function rather than the linear function, which disagrees with experimental data at a low plug velocity. Front and tail plug surface curvature was scaled using dimensionless parameter, the flow rate ratio multiplied by Capillary number based on bulk velocity (Qd/Qc * Cabulk). Instantaneous velocity vector fields inside water plugs were measured by means of PTV technique. Different flow structures were found and discussed. As a result, it is proposed to use the values of Qd/Qc * Cabulk for distinguishing different plug shapes and circulation patterns inside the plugs.

AB - We present an experimental study of the liquid-liquid system with extremely low viscosity ratio (10−3) in a T-shaped microchannel with 120 × 120 μm inlets and a 240 × 120 μm outlet channel. Six different flow patterns have been observed: plug, droplet, slug, throat-annular and parallel flow. A specific plug flow pattern was found where micron-sized droplets or even a jet breaks off from the rear meniscus of a plug. In addition to typical Taylor-shaped plugs the dumbbell-like plugs were observed. Flow visualization data were summarized in the flow pattern maps. Plug length and velocity were measured based on flow visualization results. It was found that the plug velocity can be fitted by power function rather than the linear function, which disagrees with experimental data at a low plug velocity. Front and tail plug surface curvature was scaled using dimensionless parameter, the flow rate ratio multiplied by Capillary number based on bulk velocity (Qd/Qc * Cabulk). Instantaneous velocity vector fields inside water plugs were measured by means of PTV technique. Different flow structures were found and discussed. As a result, it is proposed to use the values of Qd/Qc * Cabulk for distinguishing different plug shapes and circulation patterns inside the plugs.

KW - Flow pattern map

KW - Hydrodynamics

KW - Liquid-liquid flow

KW - Microchannel

KW - Plug flow

KW - PTV

KW - 2-PHASE FLOW

KW - PATTERNS

KW - INTENSIFICATION

KW - SLUG-FLOW

KW - PRESSURE-DROP

KW - CAPILLARY-MICROREACTOR

KW - EXTRACTION

KW - SYSTEMS

KW - FABRICATION

KW - MASS-TRANSFER

UR - http://www.scopus.com/inward/record.url?scp=85049299220&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2018.07.013

DO - 10.1016/j.cej.2018.07.013

M3 - Article

AN - SCOPUS:85049299220

VL - 352

SP - 120

EP - 132

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

SN - 1385-8947

ER -