International Scientific Journal


Drop formation in cross-junction micochannels is numerically studied using the lattice Boltzmann method with pseudo-potential model. To verify the simulation, the results are compared to previous numerical and experimental data. Furthermore, the effects of capillary number, flow rate ratio, contact angle and viscosity ratio on the flow patterns, drop length and interval between drops are investigated and highlighted. The results show that the drop forming process has different regimes, namely, jetting, drop and squeezing regimes. Also, it is shown that increasing in the flow rate ratio in the squeezing regime causes increment in drop length and decrement in drops interval distance. On the other hand, the drops length and the interval between the generated drops increase as contact angle increases. Also, the drop length and distance between drops is solely affected by viscosity ratio.
PAPER REVISED: 2016-08-30
PAPER ACCEPTED: 2016-09-02
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2018, VOLUME 22, ISSUE Issue 2, PAGES [909 - 919]
  1. He,M., et al., Selective Encapsulation of Single Cells and Subcellular Organelles into Picoliter- and Femtoliter-volume Droplets, Anal. Chem., 77 (2005), 6,pp. 1539-1544.
  2. Chambers, R.D., et al., Elemental Fluorine- Part 13. Gas-liquid Thin Film Microreactors for Selective Direct Fluorination,Lab on a Chip 1, (2001), pp. 132-137.
  3. Griffiths, A. D., Tawfik, D.S., Miniaturising the Laboratory in Emulsion Droplets, Trends Biotechnol., 24 (2006),pp.395-402.
  4. Kobayashi, J., et al.,A Microfluidic Device for Conducting Gas-liquid-solid Hydrogenation Reactions,Science, 304 (2004), 1305-1308.
  5. Thorsen, T., et al., Dynamic Pattern Formation in a Vesicle-generating Microfluidic Device,Phys Rev. Lett.,86 (2001), 18, pp. 4163-4166.
  6. Christopher, G. F, et al., Experimental Observations of the Squeezing-to-dripping Transition in T-shaped Microfluidic Junctions,Phys Rev E.,78 (2008), 3,36317.
  7. Sivasamy, J., et al.,An Investigation on the Mechanism of Droplet Formation in a Microfluidic T-Junction, 11 (2011), 1, pp 1-10.
  8. Qian, D., Lawal, A., Numerical Study on Gas and Liquid Slugs for Taylor Flow in a T-junction microchannel, Chemical Engineering Science, 61 (2006), pp. 7609 - 7625.
  9. Shi, Y., Lattice Boltzmann Simulation of Droplet Formation and Flow Focusing Devices, Computers and Fluids, 90 (2014), pp. 155-63.
  10. Tice, J.D., et al., Formation of Droplets and Mixing in Multiphase Microfluidics at Low Values of the Reynolds and the Capillary Numbers, Langmuir, 19 (2003), 9127-9133.
  11. Kim, K. C., et al., Simultaneous Measurement of Internal and External Flow Fields around the Droplet Formation in a Microchannel, proc. Of 4th KSV Conf., Korea, (2004) 80-83.
  12. Cubaud, Th., et al., Two-phase Flow in Microchannels with Surface Modifications, Fluid Dynamics Research 38 (2006), pp. 772-786.
  13. Wu, L., et al., Three-dimensional Lattice Boltzmann Simulations of Droplet Formation in a Cross-junction Microchannel, International Journal of Multiphase Flow, 14 (2008), pp. 852-864.
  14. Fu, T.,et al.,Breakup dynamics of Slender Formation in Shear-thinning Fluids in Flow-focusing Devices, 144 (2016), pp. 75-86.
  15. Yue, J., et al., An Experimental Investigation of Gas-liquid Two-phase Flow in Single Microchannel Contactors, Chemical Engineering Science, 63 (2008),pp. 4189 - 4202.
  16. Chaoqun, Y., et al., Characteristics of Slug Flow with Inertial Effects in a Rectangular Microchannel, Chemical Engineering Science, 95(2013), pp. 246-256.
  17. Carrol, B., Hidrovo, C., Experimental Investigation of Inertial Mixing in Colliding Droplets, Heat Transfer Engineering, 34 (2013), pp. 120-130.
  18. Gupta, A., Kumar, R., Lattice Boltzmann Simulation to Study Multiple Bubble Dynamics, Int J Heat Mass Transf.,51 (2008), 5, pp. 5192-5203.
  19. Sajjadi, H., Kefayati, R., Lattice Boltzmann simulation of turbulent natural convection in tall enclosures, THERMAL SCIENCE International Scientific Journal, Vol. 19 (2015), pp. 155-166.
  20. Fallah, K., et al., Simulation of natural convection heat transfer using nanofluid in a concentric annulus, THERMAL SCIENCE International Scientific Journal, 2015. doi: 10.2298/TSCI150118078F.
  21. Alinejad, J., Fallah, K., Taguchi Optimization Approach for Three-Dimensional Nanofluid Natural Convection in a Transformable Enclosure, Journal of Thermophysics and Heat Transfer, doi: 10.2514/1.T4894.
  22. Fallah, K., et al., Multiple-relaxation-time lattice Boltzmann simulation of non-Newtonian flows past a rotating circular cylinder. Journal of Non-Newtonian Fluid Mechanics, Vol. 177 (2012), pp. 1-14.
  23. Wang Y-L., Shao X-M., Study on flow of power-law fluid through an infinite array of circular cylinders with immersed boundary-lattice Boltzmann method, THERMAL SCIENCE International Scientific Journal, Vol. 16 (5) (2012), pp. 1451-1455.
  24. Fallah, K., et al., Numerical simulation of planar shear flow passing a rotating cylinder at low Reynolds numbers, Acta Mechanica, Vol. 223 (2012), pp. 221-236.
  25. Inamuro, T., et al., A lattice Boltzmann method for incompressible two-phase flows with large density differences, Journal of Computational Physics, Vol. 198 (2004), pp. 628-644.
  26. Swift, M. R., et al., Lattice Boltzmann Simulation of Nonideal Fluids, Phys. Rev. Lett., 75 (1995), pp. 830-833.
  27. Swift, E. et al., Lattice Boltzmann Simulations of Liquid-gas and Binary Fluid systems, Phys. Rev. E 54 (1996) 5041-5052.
  28. He, X., et al., Discrete Boltzmann Equation Model for Nonideal Gases, Phys. Rev. E 57 (1) (1998) R13.
  29. Xiaoyi He, et al., A Lattice Boltzmann Scheme for Incompressible Multiphase Flow and its Application in Simulation of Rayleigh-Taylor Instability, J. Comput. Phys., 152 (2) (1999) 642-663.
  30. X. Shan, H. Chen, Lattice Boltzmann Model for Simulating Flows with Multiple Phases and Components, Phys. Rev. E 47 (1993) 1815-1819.
  31. X. Shan, G. Doolen, Multicomponent Lattice-Boltzmann Model with Interparticle Interaction, J. Stat. Phys.,81 (1995) 379-393.
  32. Luo, L.S., Unified Theory of Lattice Boltzmann Models for Nonideal Gases, Phys. Rev. Lett., 81 (1998), pp. 1618-1621.
  33. Luo, L.S., Some Recent Results on Discrete Velocity Models and Ramifications for Lattice Boltzmann Equation, Comput. Phys. Commun., 129 (2000), pp. 63-74.
  34. Bao, J., Schaefer, L., Lattice Boltzmann Equation Model for Multi-component Multi-phase Flow with High Density Ratios, Applied Mathematical Modelling, 37 (2013), pp. 1860-1871.
  35. Huang, H., et al., Proposed Approximation for Contact Angles in Shan-and-Chen-type Multicomponent Multiphase Lattice Boltzmann Models. Phys. Rev. E., 76, 066701 (2007).
  36. Shan,X., Chen, H., Simulation of Nonideal Gases and Liquid-gas Phase Transitions by the Lattice Boltzmann Equation, Phys. Rev. E., 49 (1994), 4, 2941
  37. Yuan, P., Schaefer, L.,Equations of State in a Lattice Boltzmann Model, Phys. Fluids, 18 (2006), 042101.
  38. Zou, Q., He, X., On Pressure and Velocity Boundary Conditions for the Lattice Boltzmann BGK Model. Phys Fluids, 9 (1997), 6,
  39. Izquierdo, S., et al.,Analysis of Open Boundary Effects in Unsteady Lattice Boltzmann Simulations, Computers and Mathematics with Applications 58 (2009) 914_921.
  40. Succi, S., The Lattice Boltzamnn Equation for Fluid Mechanics and Beyond. Oxford-Clarendon, Oxford. 2001.

© 2022 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence