Numerical investigation on splitting of ferrofluid microdroplets in T-junctions using an asymmetric magnetic field with proposed correlation

Aboutalebi, M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jmmm.2017.09.053
  3. Publisher: Elsevier B.V , 2018
  4. Abstract:
  5. The studies surrounding the concept of microdroplets have seen a dramatic increase in recent years. Microdroplets have applications in different fields such as chemical synthesis, biology, separation processes and micro-pumps. This study numerically investigates the effect of different parameters such as Capillary number, Length of droplets, and Magnetic Bond number on the splitting process of ferrofluid microdroplets in symmetric T-junctions using an asymmetric magnetic field. The use of said field that is applied asymmetrically to the T-junction center helps us control the splitting of ferrofluid microdroplets. During the process of numerical simulation, a magnetic field with various strengths from a dipole located at a constant distance from the center of the T-junction was applied. The main advantage of this design is its control over the splitting ratio of daughter droplets and reaching various microdroplet sizes in a T-junction by adjusting the magnetic field strength. The results showed that by increasing the strength of the magnetic field, the possibility of asymmetric splitting of microdroplets increases in a way that for high values of field strength, high splitting ratios can be reached. Also, by using the obtained results at various Magnetic Bond numbers and performing curve fitting, a correlation is derived that can be used to accurately predict the borderline between splitting and non-splitting zones of microdroplets flow in micro T-junctions. © 2017
  6. Keywords:
  7. Droplet splitting ; Ferrofluid droplet ; Microfluidics ; T-junction ; Curve fitting ; Drops ; Magnetic fields ; Magnetism ; Asymmetric splitting ; Capillary numbers ; Daughter droplets ; Magnetic field strengths ; Numerical investigations ; Separation process ; Splitting process ; T junctions ; Intersections
  8. Source: Journal of Magnetism and Magnetic Materials ; Volume 447 , February , 2018 , Pages 139-149 ; 03048853 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0304885317305565