Intensification of the liquid side mass transfer in double-side falling film microchannels by micro-mixing structures

Chen, Siyuan; Zhang, Tao; Lv, Li; Chen, Yanxiao; Yongchang, Yang; Tang, Shengwei

doi:10.1016/j.ces.2018.09.016

Cited by 24 publications

(11 citation statements)

References 32 publications

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“…Conventional CFD techniques are used for the numerical simulations in all previous works, whereas a modified IBM is employed in the present work. This hybrid technique eliminates almost all disadvantages pertaining to general active and passive mixing methods in micro channels (Ahmed et al, 2009;Luong et al, 2011;Campisi et al, 2009;Mahammedi et al, 2017;Islami et al, 2017;Ababaei et al, 2017;Cho, 2008;Lim et al, 2010;Du et al, 2010;Buchegger et al, 2011;Neerincx et al, 2011;Isfahani et al, 2018;Nayak et al, 2018;Borgohain et al, 2018;Chen et al, 2019;Fan et al, 2019).…”

Section: Significance and Noveltymentioning

confidence: 99%

Pressure-Driven Electro-Osmotic Flow and Mass Transport in Constricted Mixing Micro-Channels

Ahamed

Algahtani

Badruddin

et al. 2020

JAFM

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Both micro electro mechanical systems (MEMS) based and lab-on-a chip (LoC) devices demand efficient micro-scale mixing mechanisms for its effective control which necessitates the quality research towards more efficient designs. A new venture is investigated in those direction with mixing micro-channel constricted with rectangular block under pressure-driven electro-osmotic flow and is numerically simulated by a modified immersed boundary method (IBM), an alternative technique in computational fluid dynamics (CFD). The electro-osmotic flow elucidated by electrical double layer theory when simultaneously considered with pressure driven flow in micro channels can be effectively figured out by the solution of Navier-Stokes equations linked with Nernst-Planck and Poisson equations for transportation of ion and electric field respectively. In this study, the effect of varying the height of rectangular block on the flow and mixing performance are analyzed. A hybrid method, which is a combination of active and passive techniques, is introduced simultaneously in the microchannel by the electro-osmotic effects and channel constriction. The approach is on the basis of finite volume methodology on a staggered mesh. The governing equations are solved by a time-integration technique based on a fractional step method. The velocity fields are corrected by a pseudo-pressure term to ensure the continuity in each computational time step. The extent of mixing in every cross section of the micro channel is assessed by a suitable mixing efficiency parameter. This study has shed light on the most predominant factors that influence mixing efficiency in a micro-channel, such as geometry of the block, non-dimensional numbers (Reynolds number, Re and Peclet number, Pe), zeta potential, external electric field strength and electrical double layer (EDL) thickness. The maximum efficiency in this micro mixer design is found to be 51.3% for Reynolds number of 0.05 and Peclet number of 450 with the rectangular block height of 0.75. It is clear that both electro osmotic effects and flow perturbations due to channel constriction caused a remarkable improvement in mixing efficiency. The outcomes of this investigation are widely applicable in cooling of microchips, heat sinks of MEMS based devices, drug delivery applications and Deoxyribonucleic acid (DNA) hybridization. The present IBM model is validated by experimental and numerical results from the literature.

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Section: Significance and Noveltymentioning

confidence: 99%

Pressure-Driven Electro-Osmotic Flow and Mass Transport in Constricted Mixing Micro-Channels

Ahamed

Algahtani

Badruddin

et al. 2020

JAFM

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“…The formation of rivulets is especially reduced by the microstructuring. Recently, Chen et al 24 showed that mixing structures in a falling film reactor gives rise to increased mass transfer due to induced mixing. The microstructured devices in both studies were manufactured using conventional techniques.…”

Section: Introductionmentioning

confidence: 99%

Regular Microstructured Elements for Intensification of Gas–Liquid Contacting Made by Selective Laser Melting

Grinschek

Xie

Klumpp

et al. 2019

Ind. Eng. Chem. Res.

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Additive manufacturing (AM) as a novel technique for generating complex geometries is attracting interest in R&D. Besides the vast opportunities in rapid prototyping and manufacturing, especially in the chemical industry, the extended possibilities of producing devices highly adapted to specific tasks are opening new avenues for process intensification and miniaturization. In this work 3D-structured components for fluidic devices manufactured by selective laser melting are presented. Fluid guiding elements (FGE) structured with precisely defined fluid passages in the submillimeter range for absorption processes were additively manufactured. The elements were characterized and evaluated for CO 2 absorption in water and NaOH solution. In general, the FGE structures show enhanced gas−liquid mass transfer in CO 2 absorption. The absorption coefficient k l for CO 2 in water is in the same range as reported for microstructured falling film devices. This example demonstrates the opportunity of using AM to produce innovative fluidic devices.

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“…Additionally, equations for determining the averaged film thickness, the averaged velocity vectors over the film thickness, the longitudinal and vertical velocity components, and the initial angle of streamline deviation from the vertical axis were analytically obtained.Energies 2020, 13, 1938 2 of 15 the fluid film movement, heat and mass transfer in column equipment, the separation of gas-liquid mixtures, and fluid flow in heat exchangers. Scientists for the above purpose have investigated the heat and mass transfer processes occurring in microchannels [3][4][5][6] and free and induced liquid film flow over different surfaces [7][8][9][10][11][12][13][14][15][16][17][18] and inside of different channels [19][20][21][22][23][24][25]. This flow occurs due to the influence of various forces, which determine the film formation or destruction, and the inclination angle of the surface.…”

mentioning

confidence: 99%

“…This flow occurs due to the influence of various forces, which determine the film formation or destruction, and the inclination angle of the surface. At the same time, the developed mathematical models and correlation coefficients proposed for them should consider each of the above process features, and the possibility of changing the physical state of the flow components forms a liquid film (condensation, evaporation).The liquid film motion inside of microchannels was considered in [3][4][5][6] by the application of numerical and experimental methods as well as developing mathematical models. The research [3] describes the development of the criterion model for the prediction of the critical heat flux premature caused by periodic liquid film movement in microchannels.…”

mentioning

confidence: 99%

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Three-Dimensional Mathematical Model of the Liquid Film Downflow on a Vertical Surface

et al. 2020

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Film downflow from captured liquid without wave formation and its destruction is one of the most important aspects in the development of separation equipment. Consequently, it is necessary to create well-organized liquid draining in areas of captured liquid. Thus, the proposed 3D mathematical model of film downflow allows for the determination of the hydrodynamic parameters of the liquid film flow and the interfacial surface. As a result, it was discovered that the interfacial surface depends on the proposed dimensionless criterion, which includes internal friction stress, channel length, and fluid density. Additionally, equations for determining the averaged film thickness, the averaged velocity vectors over the film thickness, the longitudinal and vertical velocity components, and the initial angle of streamline deviation from the vertical axis were analytically obtained.Energies 2020, 13, 1938 2 of 15 the fluid film movement, heat and mass transfer in column equipment, the separation of gas-liquid mixtures, and fluid flow in heat exchangers. Scientists for the above purpose have investigated the heat and mass transfer processes occurring in microchannels [3][4][5][6] and free and induced liquid film flow over different surfaces [7][8][9][10][11][12][13][14][15][16][17][18] and inside of different channels [19][20][21][22][23][24][25]. This flow occurs due to the influence of various forces, which determine the film formation or destruction, and the inclination angle of the surface. At the same time, the developed mathematical models and correlation coefficients proposed for them should consider each of the above process features, and the possibility of changing the physical state of the flow components forms a liquid film (condensation, evaporation).The liquid film motion inside of microchannels was considered in [3][4][5][6] by the application of numerical and experimental methods as well as developing mathematical models. The research [3] describes the development of the criterion model for the prediction of the critical heat flux premature caused by periodic liquid film movement in microchannels. The research implements the simplifications and assumptions for the Navier-Stokes equations, such as neglecting the gravity and inertia forces, considering the film movement only along the channel, and introducing the lubrication approximation. The authors of [4] studied the falling water film movement inside of microchannel with the "water-carbon dioxide" mixing section. The obtained results consider the mass exchange between two phases by numerical simulation for the case of laminar flow and multiphase VOF (volume of fluid) model with the indirect comparison between the numerical simulation and experimental results. The Lattice Boltzmann method (LBM) is commonly used for liquid flow motion in microchannels [5,6], especially in cases of studying hydrodynamic phenomena during the heat-mass transfer processes [6], which involve formation and breakup process of the liquid film in this channel type.Studies on falli...

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Intensification of the liquid side mass transfer in double-side falling film microchannels by micro-mixing structures

Cited by 24 publications

References 32 publications

Pressure-Driven Electro-Osmotic Flow and Mass Transport in Constricted Mixing Micro-Channels

Pressure-Driven Electro-Osmotic Flow and Mass Transport in Constricted Mixing Micro-Channels

Regular Microstructured Elements for Intensification of Gas–Liquid Contacting Made by Selective Laser Melting

Three-Dimensional Mathematical Model of the Liquid Film Downflow on a Vertical Surface

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