Abstract
A numerical study of aqueous droplet generation in a high Reynolds (Re) number air flow was performed in a microfluidic flow-focusing geometry. Droplet breakup mechanisms, flow regime mapping, droplet morphology, and droplet generation frequency were studied in a high initial air flow under various flow conditions. Several flow regimes were identified including dripping, unstable dripping, plugging, stratified flow, multi-satellite droplet formation, and unstable jetting. Unstable dripping, multi-satellite droplet formation, and unstable jetting have been observed as new flow regimes in our study. We found that the high inertial air flow remarkably induces the formation of these new flow regimes by retaining unique droplet generation mechanisms and morphology. In particular, the polydisperse spray of tiny droplets is formed at the junction in the multi-satellite droplet formation regime, while at the end of a jet in the unstable jetting regime. On the other hand, stable droplet generation occurs in the dripping and plugging regimes, while generated droplets in the unstable dripping, unstable jetting, and multi-satellite droplet formation regimes are unstable. The maximum generation frequency of ~ 1900 Hz was obtained under the unstable dripping regime. It was found that increasing Re number results in droplet size reduction, while higher capillary (Ca) number leads to bigger droplets.
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References
C.H. Ahn, J.-W. Choi, G. Beaucage, J.H. Nevin, J.-B. Lee, A. Puntambekar, J.Y. Lee, Disposable smart lab on a chip for point-of-care clinical diagnostics. Proc. IEEE 92(1), 154–173 (2004). https://doi.org/10.1109/JPROC.2003.820548
B. Carroll, C. Hidrovo, Experimental investigation of inertial mixing in colliding droplets. Heat Transfer Eng. 34(2–3), 120–130 (2013). https://doi.org/10.1080/01457632.2013.703087
X. Chen, C.L. Ren, A microfluidic chip integrated with droplet generation, pairing, trapping, merging, mixing and releasing. RSC Adv. 7(27), 16738–16750 (2017). https://doi.org/10.1039/C7RA02336G
W.L. Cheng, R. Sadr, J. Dai, A. Han, Prediction of microdroplet breakup regime in asymmetric T-junction microchannels. Biomed. Microdevices 20(3), 72 (2018). https://doi.org/10.1007/s10544-018-0310-8
D. Chong, X. Liu, H. Ma, G. Huang, Y.L. Han, X. Cui, J. Yan, F. Xu, Advances in fabricating double-emulsion droplets and their biomedical applications. Microfluid. Nanofluid. 19(5), 1071–1090 (2015). https://doi.org/10.1007/s10404-015-1635-8
M.B. Dolovich, R. Dhand, Aerosol drug delivery: Developments in device design and clinical use. Lancet (London, England) 377(9770), 1032–1045 (2011). https://doi.org/10.1016/S0140-6736(10)60926-9
W.J. Duncanson, T. Lin, A.R. Abate, S. Seiffert, R.K. Shah, D.A. Weitz, Microfluidic synthesis of advanced microparticles for encapsulation and controlled release. Lab Chip 12(12), 2135–2145 (2012). https://doi.org/10.1039/C2LC21164E
R. Fan, K. Naqvi, K. Patel, J. Sun, J. Wan, Evaporation-based microfluidic production of oil-free cell-containing hydrogel particles. Biomicrofluidics 9(5), 052602 (2015). https://doi.org/10.1063/1.4916508
N. Firoozi, A.H. Rezayan, S.J.T. Rezaei, M. Mir-Derikvand, M.R. Nabid, J. Nourmohammadi, J.M. Arough, Synthesis of poly(ε-caprolactone)-based polyurethane semi-interpenetrating polymer networks as scaffolds for skin tissue regeneration. Int. J. Polym. Mater. Polym. Biomater. 66(16), 805–811 (2017). https://doi.org/10.1080/00914037.2016.1276059
H. Gu, M.H.G. Duits, F. Mugele, Droplets formation and merging in two-phase flow microfluidics. Int. J. Mol. Sci. 12(4), 2572–2597 (2011). https://doi.org/10.3390/ijms12042572
F. Guo, B. Chen, Numerical study on Taylor bubble formation in a micro-channel T-junction using VOF method. Microgravity Sci. Technol. 21(1), 51–58 (2009). https://doi.org/10.1007/s12217-009-9146-4
A.C. Hatch, J.S. Fisher, S.L. Pentoney, D.L. Yang, A.P. Lee, Tunable 3D droplet self-assembly for ultra-high-density digital micro-reactor arrays. Lab Chip 11(15), 2509–2517 (2011). https://doi.org/10.1039/c0lc00553c
D.M. Headen, J.R. García, A.J. García, Parallel droplet microfluidics for high throughput cell encapsulation and synthetic microgel generation. Microsyst. Nanoeng. 4, 17076 (2018). https://doi.org/10.1038/micronano.2017.76
P.H. Hoang, L.Q. Dien, Fast synthesis of an inorganic–organic block copolymer in a droplet-based microreactor. RSC Adv. 4(16), 8283–8288 (2014). https://doi.org/10.1039/C3RA45747H
M. Iqbal, Y. Tao, S. Xie, Y. Zhu, D. Chen, X. Wang, L. Huang, D. Peng, A. Sattar, M.A.B. Shabbir, H.I. Hussain, S. Ahmed, Z. Yuan, Aqueous two-phase system (ATPS): An overview and advances in its applications. Biol. Proced. Online. 18(1), 18 (2016). https://doi.org/10.1186/s12575-016-0048-8
M. Jang, S. Yang, P. Kim, Microdroplet-based cell culture models and their application. BioChip J. 10(4), 310–317 (2016). https://doi.org/10.1007/s13206-016-0407-1
K. Jiang, A.X. Lu, P. Dimitrakopoulos, D.L. DeVoe, S.R. Raghavan, Microfluidic generation of uniform water droplets using gas as the continuous phase. J. Colloid Interface Sci. 448, 275–279 (2015). https://doi.org/10.1016/j.jcis.2015.02.023
S. Kashani, A.A. Ranjbar, M. Mastiani, H. Mirzaei, Entropy generation and natural convection of nanoparticle-water mixture (nanofluid) near water density inversion in an enclosure with various patterns of vertical wavy walls. Appl. Math. Comput. 226, 180–193 (2014). https://doi.org/10.1016/j.amc.2013.10.054
C.H. Kwak, S.-M. Kang, E. Jung, Y. Haldorai, Y.-K. Han, W.-S. Kim, T. Yu, Y.S. Huh, Customized microfluidic reactor based on droplet formation for the synthesis of monodispersed silver nanoparticles. J. Ind. Eng. Chem. 63, 405–410 (2018). https://doi.org/10.1016/j.jiec.2018.02.040
X.-B. Li, F.-C. Li, J.-C. Yang, H. Kinoshita, M. Oishi, M. Oshima, Study on the mechanism of droplet formation in T-junction microchannel. Chem. Eng. Sci. 69(1), 340–351 (2012). https://doi.org/10.1016/j.ces.2011.10.048
M. Mastiani, B. Mosavati, M.(.M.). Kim, Numerical simulation of high inertial liquid-in-gas droplet in a T-junction microchannel. RSC Adv. 7(77), 48512–48525 (2017). https://doi.org/10.1039/C7RA09710G
M. Mastiani, S. Seo, J. S. Melgar, N. Petrozzi, Kim M (Mike) (2017a) Understanding fundamental physics of aqueous droplet generation mechanisms in the aqueous environment. :V007T09A048. https://doi.org/10.1115/IMECE2017-71542
M. Mastiani, S. Seo, S.M. Jimenez, N. Petrozzi, M.M. Kim, Flow regime mapping of aqueous two-phase system droplets in flow-focusing geometries. Colloids Surf. A Physicochem. Eng. Asp. 531, 111–120 (2017b). https://doi.org/10.1016/j.colsurfa.2017.07.083
M. Mastiani, M.M. Kim, A. Nematollahi, Density maximum effects on mixed convection in a square lid-driven enclosure filled with cu-water nanofluids. Adv. Powder Technol. 28(1), 197–214 (2017c)
M. Mastiani, S. Seo, B. Mosavati, M. Kim, High-throughput aqueous two-phase system droplet generation by oil-free passive microfluidics. ACS Omega 3(8), 9296–9302 (2018). https://doi.org/10.1021/acsomega.8b01768
B.-U. Moon, S.G. Jones, D.K. Hwang, S.S.H. Tsai, Microfluidic generation of aqueous two-phase system (ATPS) droplets by controlled pulsating inlet pressures. Lab Chip 15(11), 2437–2444 (2015). https://doi.org/10.1039/c5lc00217f
B.-U. Moon, N. Abbasi, S.G. Jones, D.K. Hwang, S.S.H. Tsai, Water-in-water droplets by passive microfluidic flow focusing. Anal. Chem. 88(7), 3982–3989 (2016). https://doi.org/10.1021/acs.analchem.6b00225
S.M.S. Murshed, S.H. Tan, N.T. Nguyen, T.N. Wong, L. Yobas, Microdroplet formation of water and nanofluids in heat-induced microfluidic T-junction. Microfluid. Nanofluid. 6(2), 253–259 (2009). https://doi.org/10.1007/s10404-008-0323-3
S.A. Nabavi, S. Gu, G.T. Vladisavljević, E.E. Ekanem, Dynamics of double emulsion break-up in three phase glass capillary microfluidic devices. J. Colloid Interface Sci. 450, 279–287 (2015). https://doi.org/10.1016/j.jcis.2015.03.032
W.-L. Ong, J. Hua, B. Zhang, T.-Y. Teo, J. Zhuo, N.-T. Nguyen, N. Ranganathan, L. Yobas, Experimental and computational analysis of droplet formation in a high-performance flow-focusing geometry. Sensors Actuators A Phys. 138(1), 203–212 (2007). https://doi.org/10.1016/j.sna.2007.04.053
B.D. Piorek, S.J. Lee, J.G. Santiago, M. Moskovits, S. Banerjee, C.D. Meinhart, Free-surface microfluidic control of surface-enhanced Raman spectroscopy for the optimized detection of airborne molecules. Proc. Natl. Acad. Sci. U. S. A. 104(48), 18898–18901 (2007). https://doi.org/10.1073/pnas.0708596104
A.H. Rezayan, N. Firoozi, S. Kheirjou, S.J. Tabatabaei Rezaei, M.R. Nabid, Synthesis and characterization of biodegradable semi-interpenetrating polymer networks based on star-shaped copolymers of ɛ-Caprolactone and Lactide. Iran. J. Pharm. Res. 16(1), 63–73 (2017)
S.S. Sebti, M. Mastiani, H. Mirzaei, A. Dadvand, S. Kashani, S.A. Hosseini, Numerical study of the melting of nano-enhanced phase change material in a square cavity. J. Zheijang Univ. Sci. A 14(5), 307–316 (2013). https://doi.org/10.1631/jzus.A1200208
R. Seemann, M. Brinkmann, T. Pfohl, S. Herminghaus, Droplet based microfluidics. Rep. Prog. Phys. 75(1), 016601 (2012). https://doi.org/10.1088/0034-4885/75/1/016601
S. Seo, M. Nguyen, M. Mastiani, G. Navarrete, Kim M (Mike) (2017) Microbubbles loaded with nickel nanoparticles: A perspective for carbon sequestration. Anal. Chem., https://doi.org/10.1021/acs.analchem.7b02205
S. Seo, M. Mastiani, B. Mosavati, D.M. Peters, P. Mandin, M. Kim, Performance evaluation of environmentally benign nonionic biosurfactant for enhanced oil recovery. Fuel 234, 48–55 (2018). https://doi.org/10.1016/j.fuel.2018.06.111
S. Seo, M. Mastiani, M. Hafez, G. Kunkel, C. Ghattas Asfour, K.I. Garcia-Ocampo, N. Linares, C. Saldana, K. Yang, M. Kim, Injection of in-situ generated CO2 microbubbles into deep saline aquifers for enhanced carbon sequestration. Int. J. Greenh. Gas. Con. 83, 256–264 (2019). https://doi.org/10.1016/j.ijggc.2019.02.017
A. Shahriari, M.M. Kim, S. Zamani, N. Phillip, B. Nasouri, C.H. Hidrovo, Flow regime mapping of high inertial gas–liquid droplet microflows in flow-focusing geometries. Microfluid. Nanofluid. 20(1), 20 (2016). https://doi.org/10.1007/s10404-015-1671-4
G.Y. Soh, G.H. Yeoh, V. Timchenko, Numerical investigation on the velocity fields during droplet formation in a microfluidic T-junction. Chem. Eng. Sci. 139, 99–108 (2016). https://doi.org/10.1016/j.ces.2015.09.025
H. Song, D.L. Chen, R.F. Ismagilov, Reactions in droplets in microfluidic channels. Angew. Chem. Int. Ed. 45(44), 7336–7356 (2006). https://doi.org/10.1002/anie.200601554
S.-Y. Teh, R. Lin, L.-H. Hung, A.P. Lee, Droplet microfluidics. Lab Chip 8(2), 198–220 (2008). https://doi.org/10.1039/B715524G
P. Tirandazi, C.H. Hidrovo, Liquid-in-gas droplet microfluidics; experimental characterization of droplet morphology, generation frequency, and monodispersity in a flow-focusing microfluidic device. J. Micromech. Microeng. 27(7), 075020 (2017). https://doi.org/10.1088/1361-6439/aa7595
P. Tirandazi, C.H. Hidrovo, An integrated gas-liquid droplet microfluidic platform for digital sampling and detection of airborne targets. Sensors Actuators B Chem. 267, 279–293 (2018). https://doi.org/10.1016/j.snb.2018.03.057
J. Wang, J. Wang, L. Feng, T. Lin, Fluid mixing in droplet-based microfluidics with a serpentine microchannel. RSC Adv. 5(126), 104138–104144 (2015). https://doi.org/10.1039/C5RA21181F
C.-X. Zhao, A.P.J. Middelberg, Two-phase microfluidic flows. Chem. Eng. Sci. 66(7), 1394–1411 (2011). https://doi.org/10.1016/j.ces.2010.08.038
P. Zhu, L. Wang, Passive and active droplet generation with microfluidics: A review. Lab Chip 17(1), 34–75 (2016). https://doi.org/10.1039/c6lc01018k
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Mastiani, M., Seo, S., Riou, B. et al. High inertial microfluidics for droplet generation in a flow-focusing geometry. Biomed Microdevices 21, 50 (2019). https://doi.org/10.1007/s10544-019-0405-x
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DOI: https://doi.org/10.1007/s10544-019-0405-x