Preparation of black pigment with the Couette–Taylor vortex for electrophoretic displays

Kim, Myeongho; Park, Kyung Ju; Lee, Kang Uk; Kim, Myung Joon; Kim, Woo‐Sik; Kwon, Oh Joong; Kim, Jae Jeong

doi:10.1016/j.ces.2014.08.036

Cited by 13 publications

(10 citation statements)

References 33 publications

(32 reference statements)

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“…1. The flow patterns and instabilities produced in this canonical flow geometry have been extensively studied over the course of many decades [11][12][13][14][15][16][17][18][19][20][21][22], and Taylor vortex flow patterns have been used in many varied applications such as water purification [23], emulsion polymerization [24,25], liquid-liquid extraction [26,27], pigment preparation [28], photocatalysis [29], culture of animal cells [30], and cultivation of microalgae [31][32][33][34]. Nevertheless, despite the sustained and significant attention that Taylor vortex flow has received and the multiphase nature of many of its applications, multiphase TaylorCouette flow remains relatively poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Ramezani

Kong

Gao

et al. 2015

Chemical Engineering Journal

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h i g h l i g h t sMean bubble size, and size distribution in vertical gas-liquid Taylor vortex flow. Mass transfer coefficients for vertical gas-liquid Taylor vortex flow. Wall-driven shear produces prolate rather than oblate bubble shapes. Bubble size and spatial distribution explains low mass transfer coefficients. High wall area in annular geometry has significant impact on mass transfer. a b s t r a c tExperimental measurements of the volumetric liquid mass transfer and bubble size distribution in a vertically oriented semi-batch gas-liquid Taylor-Couette vortex reactor with radius ratio g = r i /r o = 0.75 and aspect ratio C = h/(r o À r i ) = 40 were performed, and the results are presented for axial and azimuthal Reynolds number ranges of Re a = 11.9-143 and Re H = 0-3.5 Â 10 4 , respectively. Based on these data, power-law correlations are presented for the dimensionless Sauter mean diameter, bubble size distribution, bubble ellipticity, and volumetric mass transfer coefficient in terms of relevant parameters including the axial and azimuthal Reynolds numbers. The interaction between wall-driven Taylor vortices and the axial passage of buoyancy-driven gas bubbles leads to significantly different dependencies of the mass transfer coefficient on important operating parameters such as inner cylinder angular velocity and axial superficial gas velocity than has been observed in horizontally oriented gas-liquid Taylor vortex reactors. In general, the volumetric mass transfer coefficients in vertical Taylor vortex reactors have a weaker dependence upon both the axial and azimuthal Reynolds numbers and are smaller in magnitude than those observed in horizontal Taylor vortex reactors or in stirred tank reactors. These findings can be explained by differences in the size and spatial distribution of gas bubbles in the vertically oriented reactor in comparison with the other systems.

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Section: Introductionmentioning

confidence: 99%

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Ramezani

Kong

Gao

et al. 2015

Chemical Engineering Journal

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“…The formation of these vortices in the annulus along with the cylinders generates high shear forces with homogeneous turbulent mixing [ 18 ]. Therefore, the Taylor-Couette flow has been used for enhancing the dispersion of particles and chemical reactions [ 19 , 20 , 21 ]. Recently, it has also been utilized in exfoliating graphite into graphene or graphene oxide nanosheets [ 22 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Scalable Exfoliation of Bulk MoS2 to Single- and Few-Layers Using Toroidal Taylor Vortices

Kaushik

Jang

et al. 2018

Nanomaterials

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The production of a large amount of high-quality transition metal dichalcogenides is critical for their use in industrial applications. Here, we demonstrate the scalable exfoliation of bulk molybdenum disulfide (MoS2) powders into single- or few-layer nanosheets using the Taylor-Couette flow. The toroidal Taylor vortices generated in the Taylor-Couette flow provide efficient mixing and high shear stresses on the surfaces of materials, resulting in a more efficient exfoliation of the layered materials. The bulk MoS2 powders dispersed in N-methyl-2-pyrrolidone (NMP) were exfoliated with the Taylor-Couette flow by varying the process parameters, including the initial concentration of MoS2 in the NMP, rotation speed of the reactor, reaction time, and temperature. With a batch process at an optimal condition, half of the exfoliated MoS2 nanosheets were thinner than ~3 nm, corresponding to single to ~4 layers. The spectroscopic and microscopic analysis revealed that the exfoliated MoS2 nanosheets contained the same quality as the bulk powders without any contamination or modification. Furthermore, the continuous exfoliation of MoS2 was demonstrated by the Taylor-Couette flow reactor, which produced an exfoliated MoS2 solution with a concentration of ~0.102 mg/mL. This technique is a promising way for the scalable production of single- or few-layer MoS2 nanosheets without using hazardous intercalation materials.

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“…The flow patterns and instabilities generated for single phase flow in this system have been extensively studied [16][17][18][19][20][21][22][23][24]. Taylor-Couette reactors have also been used in several varied single and multiphase flow applications such as water purification [25], emulsion polymerization [26], liquid-liquid extraction [27], pigment preparation [28], photocatalysis [29], culture of animal cells [6], and cultivation of microalgae [30,31].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the effect of ethyl alcohol surfactant on oxygen mass transfer and bubble size distribution in an air-water multiphase Taylor-Couette vortex bioreactor

Ramezani

Legg

Haghighat

et al. 2017

Chemical Engineering Journal

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Volumetric liquid side mass transfer, bubble size distribution, and bubble shape was measured in a vertically oriented semi-batch gas-liquid Taylor-Couette vortex reactor with an aspect ratio of Γ=h/(r o -r i )=40 and radius ratio of η=r i /r o =0.75. Azimuthal Reynolds number, Axial Reynolds number and Capillary number were varied between 0 to 3.8×10 4 , 7 to 99, and 6.1×10 -6 to 76.0×10 -6 , respectively. Power-law correlations based on these data were presented for dimensionless Sauter mean diameter and Sherwood number in terms of the dimensionless parameters. Presence of ethanol as surfactant in the liquid was shown to inhibit bubble coalescence, which in addition to lowering interfacial surface tension causes a generally smaller bubble size at higher concentrations of surfactant. It was also shown that the mass transfer coefficient generally increases with higher concentrations of surfactant. Both the bubble diameter and mass transfer are influenced more at lower concentrations of surfactant, and the introduction of higher amount of ethanol causes a decrease in both parameters. Keywords Gas-liquid mass transfer, Surfactant, Sherwood number, Taylor-Couette vortex bioreactor.  The addition of surfactant decreases bubble size Nomenclature Roman a Specific gas-liquid interfacial surface area [m 2 /m 3 ] C Concentration [mg/L] d Bubble diameter [mm] D Diffusion coefficient [m 2 /s] E Ellipticity of spheroid g Gravitational acceleration [m/s 2 ] h Axial distance from the bottom of reactor [m] k Volumetric mass transfer coefficient [m/s] l Spheroid major diameter [m] m Spheroid minor diameter [m] N Impeller (inner cylinder) rotational speed [rev/s] Q Volumetric flow rate [L/min] r i Outer radius of the inner cylinder [m] r o Inner radius of the outer cylinder [m] u Superficial velocity [m/s] Greek Γ Reactor aspect ratio (Γ=h/(r o -r i )) ε G Gas holdup η Reactor radius ratio (η=r i /r o ) ω Rotational speed of the inner cylinder [rad/s]

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Preparation of black pigment with the Couette–Taylor vortex for electrophoretic displays

Cited by 13 publications

References 33 publications

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Experimental measurement of oxygen mass transfer and bubble size distribution in an air–water multiphase Taylor–Couette vortex bioreactor

Scalable Exfoliation of Bulk MoS2 to Single- and Few-Layers Using Toroidal Taylor Vortices

Experimental investigation of the effect of ethyl alcohol surfactant on oxygen mass transfer and bubble size distribution in an air-water multiphase Taylor-Couette vortex bioreactor

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