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Elucidating the mechanism of step emulsification

Andrea Montessori1,2, Marco Lauricella1, Sauro Succi1,3,4, Elad Stolovicki5, and David Weitz5,6

  • 1Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185, Rome, Italy
  • 2Department of Engineering, University of Rome “Roma Tre,” Via della Vasca Navale 79, 00141 Rome, Italy
  • 3Center for Life Nanoscience at la Sapienza, Istituto Italiano di Tecnologia, viale Regina Elena 295, I/00161, Rome, Italy
  • 4Institute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
  • 5School of Engineering and Applied Sciences, Harvard University, McKay 517 Cambridge, Massachusetts 02138, USA
  • 6Department of Physics, and School of Engineering and Applied Sciences, Harvard University, Pierce 231, 29 Oxford Street, Cambridge, Massachusetts 02138, USA

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Phys. Rev. Fluids 3, 072202(R) – Published 30 July, 2018

DOI: https://doi.org/10.1103/PhysRevFluids.3.072202

Abstract

Three-dimensional, time-dependent direct simulations of step emulsification microdevices highlight two essential mechanisms for droplet formation: first, the onset of an adverse pressure gradient driving a backflow of the continuous phase from the external reservoir to the microchannel, and second, the striction of the flowing jet which leads to its subsequent rupture. It is also shown that such a rupture is delayed and eventually suppressed by increasing the flow speed of the dispersed phase within the channel, due to the stabilizing effect of dynamic pressure. This suggests a new criterion for dripping-jetting transition, based on local values of the capillary and Weber numbers.

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References (30)

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Outline

Information

Phys. Rev. Fluids 3, 072202(R)– Published 30 July, 2018
  • Received 22 March 2018
  • Revised 14 May 2018
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