Issue 5, 2021

Splitting dynamics of ferrofluid droplets inside a microfluidic T-junction using a pulse-width modulated magnetic field in micro-magnetofluidics

Abstract

Micro-magnetofluidics offers a promising tool for better control over the ferrofluid droplet manipulation which has been vastly utilized in biomedical applications in recent years. In this study, the ferrofluid droplet splitting under an asymmetric Pulse-Width-Modulated (PWM) magnetic field in a T-junction is numerically investigated using a finite volume method and VOF two-phase model. By utilizing the PWM magnetic field, two novel regimes of ferrofluid droplet splitting named as Flowing through the Same Branch (FSB) and Double Splitting (DS) have been observed for the first time. In the FSB regime, the daughter droplets move out of the same microchannel outlet, and in the DS regime, the droplet splitting occurs two times which results in generating three daughter droplets. The main problem related to the asymmetric droplet splitting under a steady magnetic field is daughter droplet trapping. By using a PWM magnetic field, this issue is resolved and the trapped/escaped regions are obtained in terms of the duty cycle and dimensionless magnetic field frequency. The effects of six important dimensionless parameters on the splitting ratio, including magnetic Bond number, duty cycle, dimensionless magnetic field frequency, capillary number, dimensionless mother droplet length, and dimensionless dipole position are investigated. The results showed that the splitting ratio increases with increasing magnetic Bond number or duty cycle, or decreasing the dimensionless magnetic field frequency. Eventually, a correlation is offered for the splitting ratio based on the dimensionless variables with an average relative error of 2.67%.

Graphical abstract: Splitting dynamics of ferrofluid droplets inside a microfluidic T-junction using a pulse-width modulated magnetic field in micro-magnetofluidics

Article information

Article type
Paper
Submitted
02 Okt. 2020
Accepted
20 Nov. 2020
First published
23 Nov. 2020

Soft Matter, 2021,17, 1317-1329

Splitting dynamics of ferrofluid droplets inside a microfluidic T-junction using a pulse-width modulated magnetic field in micro-magnetofluidics

M. A. Bijarchi, M. Dizani, M. Honarmand and M. B. Shafii, Soft Matter, 2021, 17, 1317 DOI: 10.1039/D0SM01764G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements