Droplet and bubble dispersion in step T-junction microchannel

CHEN Yuchao1 CUI Yongjin1 WANG Kai1 LUO Guangsheng1

(1.Department of Chemical Engineering, State Key Laboratory of Chemical Engineering, Tsinghua University, Beijing, China 100084)

【Abstract】A high-speed camera was used to study the dispersion of droplets and bubbles in a stepped T-junction microchannel embedded in a capillary. The effects of two-phase flow, viscosity, and surfactant on the flow pattern and the size of droplets and bubbles were investigated. The results show that for the droplet dispersion system, the flow pattern is determined by the concentration of the surfactant and the continuous-phase flow rate. The flow pattern changes from dripping flow to jetting flow as the two factors increase. For the bubble dispersion system, only the squeezing and dripping flow patterns exist. Addition of the surfactant has almost no effect on the bubble dispersion. The droplet and bubble size can be much smaller than the channel size. The mathematical models for predicting the dispersion size in different systems are established, and the models have good prediction performance.

【Keywords】 microchannels; microfluidics; multiphase flow; microdispersion; flow pattern;

【DOI】

【Funds】 National Key Research and Development Program of China (2017YFB0307102) National Natural Science Foundation of China (91334201)

Download this article

(Translated by WANG YX)

    References

    [1] Calabrese G S, Pissavini S. From batch to continuous flow processing in chemicals manufacturing [J]. AICh E Journal, 2011, 57 (4): 828–834.

    [2] Kashid M N, Kiwi-Minsker L. Microstructured reactors for multiphase reactions: state of the art [J]. Industrial & Engineering Chemistry Research, 2009, 48 (14): 6465–6485.

    [3] Hartman R L, Jensen K F. Microchemical systems for continuous flow synthesis [J]. Lab Chip, 2009, 9 (17): 2495–507.

    [4] Tostado C P, Xu J, Luo G. The effects of hydrophilic surfactant concentration and flow ratio on dynamic wetting in a T-junction microfluidic device [J]. Chemical Engineering Journal, 2011, 171 (3): 1340–1347.

    [5] Utada A S, Fernandez-Nieves A, Stone H A, et al. Dripping to jetting transitions in coflowing liquid streams [J]. Phys. Rev. Lett., 2007, 99 (9): 094502.

    [6] Xu J H, Li S W, Tan J, et al. Preparation of highly monodisperse droplet in a T-junction microfluidic device [J]. AICh E Journal, 2006, 52 (9): 3005–3010.

    [7] Guillot P, Colin A, Utada A S, et al. Stability of a jet in confined pressure-driven biphasic flows at low Reynolds numbers [J]. Phys. Rev. Lett., 2007, 99 (10): 104502.

    [8] Anna S L, Bontoux N, Stone H A. Formation of dispersions using “flow focusing” in microchannels [J]. Applied Physics Letters, 2003, 82 (3): 364–366.

    [9] Xu J H, Li S W, Chen G G, et al. Formation of monodisperse microbubbles in a microfluidic device [J]. AICh E Journal, 2006, 52 (6): 2254–2259.

    [10] Cramer C, Fischer P, Windhab E J. Drop formation in a coflowing ambient fluid [J]. Chemical Engineering Science, 2004, 59 (15): 3045–3058.

    [11] Xiong R, Chung J N. Bubble generation and transport in a microfluidic device with high aspect ratio [J]. Experimental Thermal and Fluid Science, 2009, 33 (8): 1156–1162.

    [12] Ganan-Calvo A M, Gordillo J M. Perfectly monodisperse microbubbling by capillary flow focusing [J]. Phys. Rev. Lett., 2001, 87 (27 Pt 1): 274501.

    [13] De Menech M, Garstecki P, Jousse F, et al. Transition from squeezing to dripping in a microfluidic T-shaped junction [J]. Journal of Fluid Mechanics, 2008, 595: 141–161.

    [14] Fu T, Ma Y. Bubble formation and breakup dynamics in microfluidic devices: a review [J]. Chemical Engineering Science, 2015, 135: 343–372.

    [15] Salman W, Gavriilidis A, Angeli P. On the formation of Taylor bubbles in small tubes [J]. Chemical Engineering Science, 2006, 61 (20): 6653–6666.

    [16] Tan J, Li S W, Wang K, et al. Gas–liquid flow in T-junction microfluidic devices with a new perpendicular rupturing flow route [J]. Chemical Engineering Journal, 2009, 146 (3): 428–433.

    [17] Vansteene A, Jasmin J P, Cavadias S, et al. Towards chip prototyping: a model for droplet formation at both T and X-junctions in dripping regime [J]. Microfluidics and Nanofluidics, 2018, 22 (6): 61.

    [18] Yoon D H, Tanaka D, Sekiguchi T, et al. Structural formation of oil-in-water (O/W) and water-in-oil-in-water (W/O/W) droplets in PDMS device using protrusion channel without hydrophilic surface treatment [J]. Micromachines (Basel), 2018, 9 (9): 468.

    [19] Gordillo J M, Cheng Z D, Ganan-Calvo A M, et al. A new device for the generation of microbubbles [J]. Physics of Fluids, 2004, 16 (8): 2828–2834.

    [20] Li Y, Wang K, Luo G. Microdroplet generation with dilute surfactant concentration in a modified T-junction device [J]. Industrial & Engineering Chemistry Research, 2017, 56 (42): 12131–12138.

    [21] Lan W J, Li S W, Xu J H, et al. Liquid–liquid two-phase viscous flow in coaxial microfluidic device [J]. CIESC Journal, 2013, 64 (2): 476–483 (in Chinese).

    [22] Li Y K, Liu G T, Xu J H, et al. A microdevice for producing monodispersed droplets under a jetting flow [J]. RSC Advances, 2015, 5 (35): 27356–27364.

    [23] Castro-Hernández E, Gundabala V, Fernández-Nieves A, et al. Scaling the drop size in coflow experiments [J]. New Journal of Physics, 2009, 11 (7), 075021.

    [24] Li Y K, Wang K, Xu J H, et al. A capillary-assembled microdevice for monodispersed small bubble and droplet generation [J]. Chemical Engineering Journal, 2016, 293: 182–188.

    [25] Castro-Hernandez E, van Hoeve W, Lohse D, et al. Microbubble generation in a co-flow device operated in a new regime [J]. Lab Chip, 2011, 11 (12): 2023.

    [26] Shih R, Bardin D, Martz T D, et al. Flow-focusing regimes for accelerated production of monodisperse drug-loadable microbubbles toward clinical-scale applications [J]. Lab Chip, 2013, 13 (24): 4816.

    [27] Xu J H, Li S W, Wang Y J, et al. Controllable gas–liquid phase flow patterns and monodisperse microbubbles in a microfluidic T-junction device [J]. Applied Physics Letters, 2006, 88 (13): 133506.

    [28] Qin K, Wang K, Luo R, et al. Dispersion of supercritical carbon dioxide to [Emim][BF4] with a T-junction tubing connector [J]. Chemical Engineering and Processing—Process Intensification, 2018, 127: 58–64.

    [29] Garstecki P, Fuerstman M J, Stone H A, et al. Formation of droplets and bubbles in a microfluidic T-junction-scaling and mechanism of break-up [J]. Lab Chip, 2006, 6 (3): 437.

    [30] Garstecki P, Stone H A, Whitesides G M. Mechanism for flowrate-controlled breakup in confined geometries: a route to monodisperse emulsions [J]. Phys. Rev. Lett., 2005, 94 (16): 164501.

    [31] Herrada M A, Ganan-Calvo A M, Montanero J M. Theoretical investigation of a technique to produce microbubbles by a microfluidic T junction [J]. Phys. Rev. E Stat. Nonlin. Soft Matter Phys., 2013, 88 (3): 033027.

This Article

ISSN:0438-1157

CN: 11-1946/TQ

Vol 71, No. 01, Pages 265-273

January 2020

Downloads:0

Share
Article Outline

Abstract

  • Introduction
  • 1 Experimental materials and methods
  • 2 Experimental results and discussion
  • 3 Conclusion
  • References