Nashrieh Shimi va Mohandesi Shimi Iran

Nashrieh Shimi va Mohandesi Shimi Iran

Numerical Simulation of Electric Droplet Formation in a Flow-Focusing Microfluidic Device

Document Type : Research Article

Authors
Sedighe Fazli 1
Salman Movahedirad 1
Sasan Asiaei 2
1 School of Chemical Engineering Iran University of Science and Technology, Tehran, I.R. IRAN
2 School of Mechanical Engineering, Iran University of Science and Technology, Tehran, I.R. IRAN
Abstract
Droplet formation process is one of the most important steps in many microfluidic proceses with biological and chemical applications. Factors affecting the droplet formation process include the geometry of the device, fluid properties, operating parameters and external forces. Since the construction of many samples to optimize the microchannel geometry is required to incur heavy costs, in this study, with the help of computational fluid dynamics technique, the droplet formation process is studied. The purpose of this study is to numerically simulate flow-focusing microchannels to study microchannel dimensions and produce small droplets under the influence of an external electrical field. The innovative aspect of the present work is the study of parameters that have not been considered in open literachar. Numerical simulation of this chip was performed in two-dimensional space. According to the flow physics, the phases of the current are assumed to be incompressible. Two geometric parameters of flow concentrating region length and orifice length were investigated. The results of this study showed that for a length of 100 μm for the flow focusing region at high voltages, the droplet diameter can be reduced to less than 55 μm. The time difference between the formation of two consecutive drops for a length of 200 μm in this region at 300V increases to 0.178 seconds. It was shown that although the length of the orifice has no considerable effect on the droplet diameter, but at the length of 90 μm, droplets are formed after the orifice. It was also shown that when the distance between the electrodes is short, smaller droplets are formed due to the increase in electrical force applied to the common boundary of the two fluids. In fact, smaller droplets can be formed by selecting the appropriate configuration for the electrodes at lower voltages.
Keywords
Microfluidic
microdroplet
Electric field
flow focusing

Subjects

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