Effect of Magnetic Field on Motion, Deformation, and Separation Time of Newtonian and Non-Newtonian Droplets in a Flow‐Focusing Microchannel

Document Type : Research Article

Authors

Department of Mechanical Engineering, Faculty of Engineering, Kharazmi University , Tehran, Iran

Abstract

In the present study, the effect of external magnetic field on the process of droplet formation with different sizes and frequencies in a flow-focusing micro-channel is numerically studied. Moreover, the influence of non-Newtonian properties on the droplet formation characteristics is investigated using two non-Newtonian Carreau and power-law models. To solve the continuity and momentum equations for unsteady, two-phase, and incompressible flow, the finite volume method is employed. A numerical algorithm based on the volume-of-fluid technique is used to determine the effect of Bond number (0 to 0.2) and Power-law indices (0.3, 0.6, and 1.3) on the droplet formation process along with their size and separation time. To validate the numerical solution, the formation of Newtonian fluid droplets at different values of magnetic field strength is compared with the results of other studies and very good agreement was observed. The results of the numerical solution show that the Carreau fluid droplet in the Bond number of 0.2 has the highest volume, which is equivalent to the dimensionless volume of 1.56. Also, the process of droplet formation is more affected by the magnetic field than by the non-Newtonian model. Besides, with developing the field strength, droplet separation time increases and as a result, larger droplets with lower frequency will be formed.

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Main Subjects

References

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Amirkabir Journal of Mechanical Engineering
Volume 53, Issue 11
February 2022
Pages 5311-5330

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