本文探討兩種不互溶流體在微流道中液滴生成和液體從晶片出口處滴
落情形，藉由ANSYS FLUENT 模擬軟件模擬兩相流體在二維T型微流道流動狀態，在不考慮兩相流體界面間的化學反應條件下，觀察兩相流體在不同體積流率和不同流道內壁面接觸角在T 型流道流動情形，以及氣體和液體在流道分段流動而液體從晶片出口處滴落時，觀察是否會被不同的流道內壁面接觸角和晶片外壁面接觸角所影響液體滴落情形。
以五種不同的流體體積流率和四種不同的流道內壁面接觸角探討液體
被氣體截斷時，氣體和液體在流道流動區塊是否獨立，以及氣體和液體在流道中各自所佔的區塊大小和流動形態關係。並探討流道內壁面接觸角和晶片外壁面接觸角對液體從晶片出口處滴落所造成的影響。
本文顯示空氣和水在T 型流道中相互擠壓及拉伸產生各自獨立區塊，
而隨著時間增加下空氣和水會重複性得到固定的獨立區塊。在兩相體積流率比為5 時，因為不同的流道內壁面接觸角所造成空氣和水在流道中形態的變化，有些流道內壁面接觸角會造成空氣和水各自獨立區塊無法產生。而液體從晶片出口處滴落的情形本文探討四種內壁面接觸角和三種外壁面接觸角對水從晶片出口處滴落的情形，得知晶片外壁面接觸角對水從晶片出口處的滴落影響會遠大於內壁面接觸角的影響。

This article discussed two immiscible fluids in microchannel droplet formation and fluid dripping case from the chip outlet, by ANSYS FLUENT software simulation of two-phase fluid in a two dimensional T-junction microchannel flow state. Without considering the chemical reaction at the interface between two phase fluids, observe the two phase fluid contact angle at different volume flow rates and different inner wall contact angle fluid flow case
in the T-junction microchannel. The gas and liquid segmented flow in the T-junction microchannel and liquid dripping case from the chip outlet, observe whether it will be a different inner wall contact angle and chip surface contact angle of liquid dripping affected situations.
Using five different volume flow rates and four different inner wall contact angle discussed the gas cut off liquid generate respective block whether independent and block size with the flow pattern of relationship. The inner wall
contact angle and the chip surface contact angle is discussed dripping case from the chip outlet caused.
This article pointed out that water and air mutual push generate respective independent block in T-junction microchannel and fixed block of time to increase. In the two-phase volume flow rate ratio is five, because the different inner wall contact angle caused by the change of air and water in the form of flow, some inner wall contact angle will cause the air and water separate block can’t produce. While the fluid dripping case from the chip outlet this article discussed four inner wall surface contact angle and three kinds of chip surface contact angle of water dripping case from the chip outlet, that the chip surface contact angle of water influence from chip outlet dripping will affect more than the inner wall surface contact angle.

[1] G. F. Christopher and S. L. Anna, "Microfluidic methods for generating continuous droplet streams," Journal of Physics D: Applied Physics, vol. 40,pp. R319-R336, 2007.
[2] A. Huebner, S. Sharma, M. Srisa-Art, F. Hollfelder, J. B. Edel, and A. J.Demello, "Microdroplets: a sea of applications?," Lab Chip, vol. 8, pp.1244-54, Aug 2008.
[3] X. Niu, S. Gulati, J. B. Edel, and A. J. deMello, "Pillar-induced droplet merging in microfluidic circuits," Lab Chip, vol. 8, pp. 1837-41, Nov 2008.
[4] S. Y. Teh, R. Lin, L. H. Hung, and A. P. Lee, "Droplet microfluidics," Lab Chip, vol. 8, pp. 198-220, Feb 2008.
[5] G. F. Christopher, J. Bergstein, N. B. End, M. Poon, C. Nguyen, and S. L. Anna, "Coalescence and splitting of confined droplets at microfluidic junctions," Lab Chip, vol. 9, pp. 1102-9, Apr 21 2009.
[6] D. Dendukuri and P. S. Doyle, "The Synthesis and Assembly of Polymeric Microparticles Using Microfluidics," Advanced Materials, vol. 21, pp.4071-4086, 2009.
[7] K.-Y. Tung, C.-C. Li, and J.-T. Yang, "Mixing and hydrodynamic analysis of a droplet in a planar serpentine micromixer," Microfluidics and Nanofluidics, vol. 7, pp. 545-557, 2009.
[8] D. Link, S. Anna, D. Weitz, and H. Stone, Geometrically Mediated Breakup of Drops in Microfluidic Devices," Physical Review Letters, vol.92, 2004.
[9] M. C. Jullien, M. J. Tsang Mui Ching, C. Cohen, L. Menetrier, and P.Tabeling, "Droplet breakup in microfluidic T-junctions at small capillary numbers," Physics of Fluids, vol. 21, p. 072001, 2009.
[10] P. Tabeling, "Investigating slippage, droplet breakup, and synthesizing microcapsules in microfluidic systems," Physics of Fluids, vol. 22, p.021302, 2010.
[11] S. J. Maerkl, "Integration column: Microfluidic high-throughput screening," Integr Biol (Camb), vol. 1, pp. 19-29, Jan 2009.
[12] C. H. Yang, Y. S. Lin, K. S. Huang, Y. C. Huang, E. C. Wang, J. Y. Jhong, et al., "Microfluidic emulsification and sorting assisted preparation of monodisperse chitosan microparticles," Lab Chip, vol. 9, pp. 145-50, Jan 7
2009.
[13] B. Ahn, K. Lee, H. Lee, R. Panchapakesan, L. Xu, J. Xu, et al., "Guiding,distribution, and storage of trains of shape-dependent droplets," Lab Chip,vol. 11, pp. 3915-8, Nov 21 2011.
[14] E. Fradet, C. McDougall, P. Abbyad, R. Dangla, D. McGloin, and C. N.Baroud, "Combining rails and anchors with laser forcing for selective manipulation within 2D droplet arrays," Lab Chip, vol. 11, p. 4228, 2011.
[15] A. Huebner, D. Bratton, G. Whyte, M. Yang, A. J. Demello, C. Abell, et al.,"Static microdroplet arrays: a microfluidic device for droplet trapping,incubation and release for enzymatic and cell-based assays," Lab Chip, vol.
9, pp. 692-8, Mar 7 2009.
[16] W. Shi, H. Wen, Y. Lu, Y. Shi, B. Lin, and J. Qin, "Droplet microfluidics for characterizing the neurotoxin-induced responses in individual Caenorhabditis elegans," Lab Chip, vol. 10, pp. 2855-63, Nov 7 2010.
[17] J. Xu, B. Ahn, H. Lee, L. Xu, K. Lee, R.Panchapakesan, et al.,"Droplet-based microfluidic device for multiple-droplet clustering," Lab Chip, vol. 12, pp. 725-30, Feb 21 2012.
[18] H. Boukellal, S. Selimovic, Y. Jia, G. Cristobal, and S. Fraden, "Simple,robust storage of drops and fluids in a microfluidic device," Lab Chip, vol.9, pp. 331-8, Jan 21 2009.
[19] Y. Schaerli and F. Hollfelder, "The potential of microfluidic water-in-oil droplets in experimental biology," Mol Biosyst, vol. 5, pp. 1392-404, Dec
2009.
[20] E. Brouzes, M. Medkova, N. Savenelli, D. Marran, M. Twardowski, J. B.Hutchison, et al., "Droplet microfluidic technology for single-cell high-throughput screening," Proc Natl Acad Sci U S A, vol. 106, pp.14195-200, Aug 25 2009.
[21] L. Kang, B. G. Chung, R. Langer, and A.hademhosseini, "Microfluidics for drug discovery and development: from target selection to product lifecycle management," Drug Discov Today, vol. 13, pp. 1-13, Jan 2008.
[22] E. Tumarkin and E. Kumacheva, "Microfluidic generation of microgels from synthetic and natural polymers," Chem Soc Rev, vol. 38, pp. 2161-8,Aug 2009.
[23] S. Marre and K. F. Jensen, "Synthesis of micro and nanostructures in microfluidic systems," Chem Soc Rev, vol. 39, pp. 1183-202, Mar 2010.
[24] J. I. Park, A. Saffari, S. Kumar, A. Günther, and E. Kumacheva,"Microfluidic Synthesis of Polymer and Inorganic Particulate Materials,"Annual Review of Materials Research, vol. 40, pp. 415-443, 2010.
[25] X. Casadevall i Solvas and A. deMello, "Droplet microfluidics: recent developments and future applications," Chem Commun (Camb), vol. 47, pp.63
1936-42, Feb 21 2011.
[26] H. Gu, M. H. Duits, and F. Mugele, "Droplets formation and merging in two-phase flow microfluidics," Int J Mol Sci, vol. 12, pp. 2572-97, 2011.
[27] J. C. Baret, "Surfactants in droplet-based microfluidics," Lab Chip, vol. 12,pp. 422-33, Feb 7 2012.
[28] L. Ménétrier-Deremble and P. Tabeling, "Droplet breakup in microfluidic junctions of arbitrary angles," Physical Review E, vol. 74, 2006.
[29] D. M. Fries and P. Rudolf von Rohr, "Impact of inlet design on mass transfer in gas–liquid rectangular microchannels," Microfluidics and Nanofluidics, vol. 6, pp. 27-35, 2008.
[30] P. Jankowski, D. Ogonczyk, A. Kosinski, W. Lisowski, and P. Garstecki,"Hydrophobic modification of polycarbonate for reproducible and stable formation of biocompatible microparticles," Lab Chip, vol. 11, pp. 748-52,Feb 21 2011.
[31] L. Shui, S. Pennathur, J. C. Eijkel, and A. van den Berg, "Multiphase flow in lab on chip devices: a real tool for the future?," Lab Chip, vol. 8, pp.1010-4, Jul 2008.
[32] W. S. Lee, S. Jambovane, D. Kim, and J. W. Hong, "Predictive model on micro droplet generation through mechanical cutting," Microfluidics and Nanofluidics, vol. 7, pp. 431-438, 2009.
[33] J. H. Choi, S. K. Lee, J. M. Lim, S. M. Yang, and G. R. Yi, "Designed pneumatic valve actuators for controlled droplet breakup and generation,"Lab Chip, vol. 10, pp. 456-61, Feb 21 2010.
[34] A. B. Wang, I. C. Lin, Y. W. Hsieh, W. P. Shih, and G. W. Wu, "Effective pressure and bubble generation in a microfluidic T-junction," Lab Chip, vol.11, pp. 3499-507, Oct 21 2011.
[35] A. Yusof, H. Keegan, C. D. Spillane, O. M. Sheils, C. M. Martin, J. J.O'Leary, et al., "Inkjet-like printing of single-cells," Lab Chip, vol. 11, pp.2447-54, Jul 21 2011.
[36] R. S. Ramsey and J. M. Ramsey, "Generating electrospray from microchip devices using electroosmotic pumping," Anal Chem, vol. 69, pp. 1174-1178,Mar 15 1997.
[37] C. N. Baroud, F. Gallaire, and R. Dangla, "Dynamics of microfluidic droplets," Lab Chip, vol. 10, pp. 2032-45, Aug 21 2010.
[38] S. van der Graaf, M. L. J. Steegmans, R. G. M. van der Sman, C. G. P. H.Schroën, and R. M. Boom, "Droplet formation in a T-shaped microchannel junction: A model system for membrane emulsification," Colloids and
Surfaces A: Physicochemical and Engineering Aspects, vol. 266, pp.106-116, 2005.
[39] P. Garstecki, M. J. Fuerstman, H. A. Stone, and G. M. Whitesides,"Formation of droplets and bubbles in a microfluidic T-junction-scaling and mechanism of break-up," Lab Chip, vol. 6, pp. 437-46, Mar 2006.
[40] J. H. Xu, G. S. Luo, S. W. Li, and G. G. Chen, "Shear force induced monodisperse droplet formation in a microfluidic device by controlling wetting properties," Lab Chip, vol. 6, pp. 131-6, Jan 2006.
[41] J. H. Xu, S. W. Li, J. Tan, and G. S. Luo, "Correlations of droplet formation
in T-junction microfluidic devices: from squeezing to dripping,"Microfluidics and Nanofluidics, vol. 5, pp. 711-717, 2008.
[42] G. F. Christopher, N. N. Noharuddin, J. A. Taylor, and S. L. Anna,"Experimental observations of the squeezing-to-dripping transition in T-shaped microfluidic junctions," Physical Review E, vol. 78, 2008.
[43] Y. X. Zhang, J. Fan, and L. Q. Wang, "Formation of Nanoliter Droplets in a Confined Microfluidic T-Shaped Junction Formation Time and Droplet Volume," Current Nanoscience, vol. 5, pp. 519-526, Nov 2009.
[44] A. R. Abate, P. Mary, V. van Steijn, and D. A. Weitz, "Experimental validation of plugging during drop formation in a T-junction," Lab Chip,vol. 12, pp. 1516-21, Apr 21 2012.
[45] M. De Menech, P. Garstecki, F. Jousse, and H. A. Stone, "Transition from squeezing to dripping in a microfluidic T-shaped junction," Journal of Fluid Mechanics, vol. 595, 2008.
[46] M. N. Kashid, A. Renken, and L. Kiwi-Minsker, "CFD modelling of liquid–liquid multiphase microstructured reactor: Slug flow generation,"Chemical Engineering Research and Design, vol. 88, pp. 362-368, 2010.
[47] R. Raj, N. Mathur, and V. V. Buwa, "Numerical Simulations of Liquid-Liquid Flows in Microchannels," Industrial & Engineering Chemistry Research, vol. 49, pp. 10606-10614, Nov 3 2010.
[48] J. Sivasamy, T.-N. Wong, N.-T. Nguyen, and L. T.-H. Kao, "An investigation on the mechanism of droplet formation in a microfluidic T-junction," Microfluidics and Nanofluidics, vol. 11, pp. 1-10, 2011.
[49] J. H. Xu, S. W. Li, Y. J. Wang, and G. S. Luo, "Controllable gas-liquid phase flow patterns and monodisperse microbubbles in a microfluidic T-junction device," Applied Physics Letters, vol. 88, p. 133506, 2006.
[50] V. Vansteijn, M. Kreutzer, and C. Kleijn, "Velocity fluctuations of segmented flow in microchannels," Chemical Engineering Journal, vol.135, pp. S159-S165, 2008.
[51] D. Qian and A. Lawal, "Numerical study on gas and liquid slugs for Taylor flow in a T-junction microchannel," Chemical Engineering Science, vol. 61,pp. 7609-7625, 2006.
[52] F. Guo and B. Chen, "Numerical Study on Taylor Bubble Formation in a Micro-channel T-Junction Using VOF Method," Microgravity Science and Technology, vol. 21, pp. 51-58, 2009.
[53] L. Dai, W. Cai, and F. Xin, "Numerical Study on Bubble Formation of a Gas-Liquid Flow in a T-Junction Microchannel," Chemical Engineering & Technology, vol. 32, pp. 1984-1991, 2009.
[54] R. M. Santos and M. Kawaji, "Numerical modeling and experimental investigation of gas–liquid slug formation in a microchannel T-junction,"International Journal of Multiphase Flow, vol. 36, pp. 314-323, 2010.
[55] V. van Steijn, C. R. Kleijn, and M. T. Kreutzer, "Predictive model for the size of bubbles and droplets created in microfluidic T-junctions," Lab Chip,vol. 10, pp. 2513-8, Oct 7 2010.
[56] X. Zhang, "Dynamics of Growth and Breakup of Viscous Pendant Drops into Air," J Colloid Interface Sci, vol. 212, pp. 107-122, Apr 1 1999.
[57] Z. Che, T. N. Wong, N.-T. Nguyen, Y. F. Yap, and J. C. Chai, "Numerical investigation of upstream pressure fluctuation during growth and breakup of pendant drops," Chemical Engineering Science, vol. 66, pp. 5293-5300,
2011.
[58] Z. Che, T. N. Wong, N.-T. Nguyen, and J. C. Chai, "Formation and breakup of compound pendant drops at the tip of a capillary and its effect on upstream velocity fluctuations," International Journal of Heat and Mass
Transfer, vol. 55, pp. 1022-1029, 2012.