Adiabatic two-phase flow in rectangular microchannels with different aspect ratios: Part I – Flow pattern, pressure drop and void fraction

Choi, Chiwoong; Yu, Dongming; Kim, M.H.

doi:10.1016/j.ijheatmasstransfer.2010.07.067

Cited by 78 publications

(39 citation statements)

References 19 publications

(27 reference statements)

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“…It is interesting that the gas hold-up and the void fraction agree reasonably well considering the experimental error and idealization of the models. The coefficient C A was determined to be 0.914 and 0.899, respectively, which was in accordance with the results of Choi et al (2011), with respect to the aspect ratio.…”

Section: Gas Hold-up and Void Fractionsupporting

confidence: 87%

“…This implies a stronger velocity slip between two phases in smaller capillaries. In rectangular microchannels (Choi et al, 2011) the void fraction all correlates well with volumetric quality in Armandtype correlation but the size effect on the coefficient C A is not clear. Their work showed a negative relationship between the coefficient C A and aspect ratio instead of hydraulic diameter.…”

Section: Gas Hold-up and Void Fractionmentioning

confidence: 93%

“…Also gas hold-up is usually used to evaluate accelerational terms in the total pressure drop of gas-liquid flow (Yue et al, 2008(Yue et al, , 2009 There are already plenty of literature studies that consider void fraction in small/micro-capillaries or channels (Choi et al, 2011;Chung and Kawaji, 2004;Ide et al, 2007;Kawahara et al, 2009Kawahara et al, , 2011Kawahara et al, , 2005Saisorn and Wongwises, 2009Xiong and Chung, 2007;Yue et al, 2008). Generally, the void fraction correlation for microchannels as a function of volumetric quality (β) can be classified to two types: linear relationship of Armand-type α¼C A β and nonlinear relationship of α¼C 1 β 0.5 /(1-C 2 β 0.5 ).…”

Section: Gas Hold-up and Void Fractionmentioning

confidence: 99%

“…These merits make slug flow an ideal regime for improving the reaction performance. Wide attention has been paid to the bubble formation process (Fu et al, 2009;Garstecki et al, 2006;Pohorecki and Kula, 2008;van Steijn et al, 2007), the gas bubble and the liquid slug length (Garstecki et al, 2006;Leclerc et al, 2010;Qian and Lawal, 2006;Sobieszuk et al, 2010), the liquid film thickness around bubbles (Fries et al, 2008;Han and Shikazono, 2009a;Thulasidas et al, 1995), the phase distribution (Choi et al, 2011;Kawahara et al, 2005;Saisorn and Wongwises, 2010), the pressure drop (Kreutzer et al, 2005a(Kreutzer et al, , 2005bYue et al, 2009), and the mass transfer (Sobieszuk et al, 2011;van Baten and Krishna, 2004;Vandu et al, 2005), etc. However, a full understanding of slug slow for optimizing the design of microreactor remains pendent.…”

Section: Introductionmentioning

confidence: 99%

“…Research on rectangular channels was motivated by the interest in monolithic reactors and by the easy fabrication of rectangular cross sections with MEMS techniques, such as photolithography and etching techniques. Moreover, the slug flow in rectangular channels presents different behaviors (Choi et al, 2011;Hazel and Heil, 2002;Kuzmin et al, 2011). Hazel and Heil (2002) investigated the steady propagation of a semi-infinite bubble into rectangular channels.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Characteristics of slug flow with inertial effects in a rectangular microchannel

Yao

Zhao

et al. 2013

Chemical Engineering Science

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Section: Gas Hold-up and Void Fractionsupporting

confidence: 87%

Section: Gas Hold-up and Void Fractionmentioning

confidence: 93%

Section: Gas Hold-up and Void Fractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characteristics of slug flow with inertial effects in a rectangular microchannel

Yao

Zhao

et al. 2013

Chemical Engineering Science

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The effect of system pressure on gas‐liquid slug flow in a microchannel

et al. 2013

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Characteristics of gas-liquid two-phase flow under elevated pressures up to 3.0 MPa in a microchannel are investigated to provide the guidance for microreactor designs relevant to industrial application. The results indicate that a strong leakage flow through the channel corners occurs although the gas bubbles block the channel. With a simplified estimation, the leakage flow is shown to increase with an increase in pressure, leading to a bubble formation shifting from transition regime to squeezing regime. During the formation process, the two-phase dynamic interaction at the Tjunction entrance would have a significant influence on the flow in the main channel as the moving velocity of generated bubbles varies periodically with the formation cycle. Other characteristics such as bubble formation frequency, bubble and slug lengths, bubble velocities, gas hold-up, and the specific surface area are also discussed under different system pressures.

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Bubble/droplet formation and mass transfer during gas–liquid–liquid segmented flow with soluble gas in a microchannel

et al. 2016

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Microchannels have great potential in intensification of gas-liquid-liquid reactions involving reacting gases, such as hydrogenation. This work uses CO 2 -octane-water system to model the hydrodynamics and mass transfer of such systems in a microchannel with double T-junctions. Segmented flows are generated with three inlet sequences and the size laws of dispersed phases are obtained. Three generation mechanisms of dispersed gas bubbles/water droplets are identified: squeezing by the oil phase, cutting by the droplet/bubble, cutting by the water-oil/gas-oil interface. Based on the gas dissolution rate, the mass transfer coefficients are calculated. It is found that water droplet can significantly enhance the transfer of CO 2 into the oil phase initially. When bubble-droplet cluster are formed downstream the microchannel, droplet will retard the mass transfer. Other characteristics such as phase hold-up, bubble velocity and bubble dissolution rate are also discussed. The information is beneficial for microreactor design when applying three-phase reactions.

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Adiabatic two-phase flow in rectangular microchannels with different aspect ratios: Part I – Flow pattern, pressure drop and void fraction

Cited by 78 publications

References 19 publications

Characteristics of slug flow with inertial effects in a rectangular microchannel

Characteristics of slug flow with inertial effects in a rectangular microchannel

The effect of system pressure on gas‐liquid slug flow in a microchannel

Bubble/droplet formation and mass transfer during gas–liquid–liquid segmented flow with soluble gas in a microchannel

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