Formation mechanisms and lengths of the bubbles and liquid slugs in a coaxial-spherical micro mixer in Taylor flow regime

Svetlov, S. D.; Абиев, Р. Ш.

doi:10.1016/j.cej.2018.07.213

Cited by 46 publications

(16 citation statements)

References 32 publications

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“…Importantly, the gas–liquid slug flow in microdevices greatly promotes the mass transfer efficiency owing to the large specific surface area and circulation flow inside slugs, which has attracted considerable attention in recent years 11,12 . Various microdevices, such as the T‐junction based on the cross‐flowing rupture technique, 13,14 co‐flowing, 15,16 and hydrodynamic flow‐focusing, 17,18 are fabricated to generate the gas–liquid slug flow. Among those microdevices, the T‐junction is the most widely used for its simple structure.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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The performances of slug flow gas–liquid reactors are mostly determined by slug length, especially for the high gas–liquid flow rate ratio condition. This work is the first time to report the short bubble generated with high frequency in a capillary embedded step T‐junction microdevice. The aspect ratio of bubble could be around 0.5 with a frequency higher than 750 s−1 when the gas–liquid flow rate ratio is even higher than 5. The specific surface area of the generated gas–liquid microdispersion system is larger than 10,400 m2/m3. The short bubble formation process includes two periods, and its formation mechanism is mainly because of the relatively higher pressure drop in the step T‐junction, which provides a much higher breakup force for the squeezing flow. Finally, two models are developed to predict the bubble frequency and volume. This work provides a highly promising dispersion technology for the gas–liquid process intensification in microreactors.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…In the past, the importance of micromixers was poorly understood, and only a few research groups focused on this area [11,12]. Recently, many new micromixer studies have been published [13][14][15][16][17]. Saygili et al produced microfluidic molds using the 3D printing method.…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of a Laminar Diffusion-Based Micromixer with Microfluidic Chip

Ülkir

Girit

Ertugrul

2021

Journal of Nanomaterials

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This study aims to perform optimizatione to achieve the best diffusion control between the channels by designing and analysing a microfluidic-based micromixer. The design and analysis of the micromixer were made with the COMSOL Multiphysics program. Some input and output parameters must be defined for diffusion control of the micromixer. Among these parameters, inputs are the diffusion coefficient and inlet flow rate, while outputs are velocity, pressure, and concentration. Each input parameter in the microfluidic chip affects the output of the system. To make the diffusion control in the most optimum way, the data were obtained by making much analysis. The data obtained from this program was also provided with the Fuzzy Logic method to optimize the microfluidic chip. The diffusion coefficient value (5E-11 m2/s) should be given to the channels to achieve the optimum diffusion between the micromixer channels, if the inlet flow rate value (15E-15 m3/s) is the output value of the system, the velocity is 0.09 mm/s. The pressure is 2 Pa, and the concentration is 0.45 mol/m3. These values are the optimum values obtained from the analysis without damaging the liquid’s microfluidic channels supplied to the micromixer’s inlet.

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“…A careful study on two‐phase flow patterns in mini‐ and microchannels was conducted by Kawaji and Chung [ 45 ] by showing the similarities and differences between these two common channels. To maintain Taylor flow in mini‐ and microchannels, Svetlov and Abiev [ 46 ] introduced a special coaxial‐spherical junction for having a slug flow regime over a wide range of phase volumetric flow rates to improve the efficiency of such channels. They also correlated the length of the bubbles to geometric dimensions, features of the mixer shape, and phase superficial velocity ratio.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of gas–liquid and liquid–liquidTaylor flow through a circular microchannel with a sudden expansion

2021

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This paper investigates a CFD‐based analysis for gas–liquid and liquid–liquid Taylor flows through a circular axisymmetric microchannel with a sudden enlargement. A series of simulations are conducted by exploring the influence of different superficial velocity ratios, apparent viscosities, and channel expansion on the hydrodynamics of slug flow. A concentric junction introduces dispersed airflow into a continuous flow of water for gas–liquid flow, and the junction introduces dispersed water into a continuous flow of dodecane for liquid–liquid flow. The air‐bubble and water‐slug evolution processes, slug breakup, and slug expansion are investigated. In all cases, the lengths of air bubbles and water slugs increase with increasing superficial velocity ratio, particularly before the expansion. For gas–liquid flow, the apparent viscosity ratio causes a fluctuating interface over the uniform film region. However, the water slug length is shorter and the film region is slightly thicker in liquid–liquid compared to gas–liquid flow. The numerical analysis developed in this paper is in good agreement with the existing correlations and experimental data in the literature.

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Formation mechanisms and lengths of the bubbles and liquid slugs in a coaxial-spherical micro mixer in Taylor flow regime

Cited by 46 publications

References 32 publications

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

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

Design and Analysis of a Laminar Diffusion-Based Micromixer with Microfluidic Chip

Numerical investigation of gas–liquid and liquid–liquidTaylor flow through a circular microchannel with a sudden expansion

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