Hydrodynamics and mass transfer in liquid-liquid non-circular microchannels: Comparison of two aspect ratios and three junction structures

Sattari-Najafabadi, Mehdi; Esfahany, Mohsen Nasr; Wu, Zan; Sundén, Bengt

doi:10.1016/j.cej.2017.04.028

Cited by 60 publications

(34 citation statements)

References 46 publications

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“…The positive relationship for low viscous fluid systems suggests that despite the enhanced absorption rate at higher CO 2 /NaOH, the finish of reaction needs more reactor volume due to the larger throughput. A similar phenomenon was also observed in liquid–liquid slug flow . The negative relationship for high viscous systems suggests that when increasing CO 2 /NaOH, the increase in absorption rate is so large that the reactor volume can be reduced.…”

Section: Resultssupporting

confidence: 68%

“…A similar phenomenon was also observed in liquid-liquid slug flow. 47 The negative relationship for high viscous systems suggests that when increasing CO 2 /NaOH, the increase in absorption rate is so large that the reactor volume can be reduced. it presented a first decrease and then a slight increase in the color change time as the glycerol concentration increases (Figure 7d).…”

Section: Distance and Time For Color Changementioning

confidence: 99%

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The effect of liquid viscosity and modeling of mass transfer in gas–liquid slug flow in a rectangular microchannel

et al. 2020

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Both chemical (by adding 0.05 M NaOH) and physical absorption of CO2 into aqueous glycerol solutions with viscosity up to 45.6 mPa·s in a microchannel are investigated. The concentration distribution pattern, absorption time, and mass transfer coefficient are analyzed and discussed. A new concentration distribution pattern is observed with the lowest concentration locating at the channel center. It is shown for the first time that kL/DitalicCO20.5 presents a positive relationship with liquid viscosity, which is explained by the essential role of the mass exchange between the liquid film and bulk liquid slug. This mass exchange may lead to a rise in k L when increasing the liquid viscosity under some cases in chemical absorption. A mass transfer model is successfully applied to predict the bubble size evolution in physical absorption. The model also shows about 10–46% of the mass transfer contribution from liquid films before saturation.

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Section: Resultssupporting

confidence: 68%

Section: Distance and Time For Color Changementioning

confidence: 99%

The effect of liquid viscosity and modeling of mass transfer in gas–liquid slug flow in a rectangular microchannel

et al. 2020

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“…However, in the range of flow conditions studied in this work, the liquid film thickness was not captured even with extremely fine meshes. Therefore, in the present study, we mainly focus our investigations towards non‐Newtonian flow behaviour in a converging microchannel to realize the effect of rheological properties on the slug length, volume, and flow profiles, thereby neglecting liquid film thickness (assuming the thickness of the liquid film between the microchannel wall and the plug surface is negligible compared to the microchannel width and depth …”

Section: Resultsmentioning

confidence: 99%

Understanding the Influence of Rheological Properties of Shear‐Thinning Liquids on Segmented Flow in Microchannel using CLSVOF Based CFD Model

et al. 2019

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In this study, two phase gas-shear-thinning liquid flow in a square microchannel is numerically investigated using the coupled level set and volume of fluid (CLSVOF) methods. A systematic investigation is carried out to explore the influence of polyacrylamide (PAM) concentration, surface tension, velocity ratios, and contact angle on the gas slug length, volume, unit cell length, and pressure drop. Three different concentrations of PAM solutions, which exhibit shear-thinning behaviour are considered as the continuous phase. Gas slug length, volume, and unit cell length decreased with increasing the PAM concentration. Velocity and non-homogeneous viscosity distributions in the liquid slug for three different PAM concentration solutions are reported. Gas slug length decreases with an increase of the contact angle and the bubble shape change from convex to concave. This numerical work provides the fundamental insights in segmented flow formation and two-phase flow characteristics comprising shear-thinning liquids.

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“…Garstecki et al [17] conducted a pioneering investigation on the process of the formation of droplets and bubbles in a T-junction microchannel, and threw light on the mechanism of the break-up of the dispersed phase fluid at a low capillary number. Sattari-Najafabadi et al [18,19] conducted experiments in cross-junction rectangular microchannels to investigate the effects of the aspect ratio and the channel size on the liquid-liquid mass transfer within the slug regime. They found that a smaller square microchannel was conducive to mass transfer.…”

Section: Introductionmentioning

confidence: 99%

Effects of a Dynamic Injection Flow Rate on Slug Generation in a Cross-Junction Square Microchannel

Qian

Chen

et al. 2019

Processes

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The injection flow rates of two liquid phases play a decisive role in the slug generation of the liquid-liquid slug flow. However, most injection flow rates so far have been constant. In order to investigate the effects of dynamic injection flow rates on the slug generation, including the slug size, separation distance and slug generation cycle time, a transient numerical model of a cross-junction square microchannel is established. The Volume of Fluid method is adopted to simulate the interface between two phases, i.e., butanol and water. The model is validated by experiments at a constant injection flow rate. Three different types of dynamic injection flow rates are applied for butanol, which are triangle, rectangular and sine wave flow rates. The dynamic injection flow rate cycles, which are related to the constant slug generation cycle time t0, are investigated. Results show that when the cycle of the disperse phase flow rate is larger than t0, the slug generation changes periodically, and the period is influenced by the cycle of the disperse phase flow rate. Among the three kinds of dynamic disperse flow rate, the rectangular wave influences the slug size most significantly, while the triangle wave influences the separation distance and the slug generation time more prominently.

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Hydrodynamics and mass transfer in liquid-liquid non-circular microchannels: Comparison of two aspect ratios and three junction structures

Cited by 60 publications

References 46 publications

The effect of liquid viscosity and modeling of mass transfer in gas–liquid slug flow in a rectangular microchannel

The effect of liquid viscosity and modeling of mass transfer in gas–liquid slug flow in a rectangular microchannel

Understanding the Influence of Rheological Properties of Shear‐Thinning Liquids on Segmented Flow in Microchannel using CLSVOF Based CFD Model

Effects of a Dynamic Injection Flow Rate on Slug Generation in a Cross-Junction Square Microchannel

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