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electrowetting
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Electrowetting-induced droplet jumping over topographically structured surfaces
, Article Materials Research Express ; Volume 6, Issue 8 , 2019 ; 20531591 (ISSN) ; Moosavi, A ; Shafii, M. B ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
We analyze the process of electrowetting-induced jumping of droplets away from a substrate with a geometric heterogeneity in the form of a cone and compare the results with those of a flat substrate in different wettabilities and hydrophobicities. Our results reveal that the droplet dynamics can be enhanced through applying a topographic heterogeneity. However, increasing the height of the cones does not always provide a better condition for the jumping and there is an optimum value for the height of the cones. The enhancement is due to the fact that more liquid flowing affects the pressure gradient within the droplet leading to a higher jumping velocity. It is shown that for the flat...
Design and Simulation of an Electrowetting Micro-Pump
,
M.Sc. Thesis
Sharif University of Technology
;
Javadi, Khodayar
(Supervisor)
Abstract
Micropumps are one of the most important devices in the field of microfluidics which have many applications in various fields of engineering. Electrostatic excitation is one of the types of excitation mechanisms in micropumps that is widely used in microelectromechanical systems due to its low power consumption and easier control. In this research, first, the physics of droplets on the surface studied, important dimensionless numbers and other factors influencing microfluidic phenomena are investigated. The effective parameters of the droplet motion and the mechanism of this motion are described. Besides, the phenomenon of electrowetting, one of the phenomena in the field of dynamics of...
The Numerical Simulation of Droplet Generation and its Control Using Electrowetting Method in Microfluidic Devices
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Shafii, Mohammad Behshad (Supervisor)
Abstract
In this research, two important mechanisms were discussed including droplet generation and jumping mechanisms using electro wetting-on-dielectric. For these purposes, the finite element method (FEM) was used to solve the unsteady Naiver-Stokes equation. In addition, the level set method was applied to capture the interface between two phases. In the current study, first, droplet generation in a T-junction fluidic channel device was studied through using electro wetting actuation. The efficacy of electro wetting on the droplet generation frequency as well as droplet diameter is visible in a T-junction fluidic channel since after applying voltages, specified with non-dimensional electro...
Design and Optimization of Digital Microfluidic Chip for Cell Sorting
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Today, microfluidics, representing the precise and controlled displacement of small amounts of fluid, is one of the most efficient tools available in various research fields, including medicine. Digital microfluidics is one of the newest microfluidic methods, which is based on the theory of electrowetting on dielectric. According to this theory, by applying a voltage difference to a droplet of fluid on a hydrophobic surface, the droplet can be moved on that surface. Therefore, by fabricating a plate containing a number of electrodes completely isolated from each other and controlling them, small droplets of fluid can be moved on a hydrophobic surface. In this thesis, the electrodes of this...
Heat transfer of power-law fluids under electrowetting actuation in structured microchannels
, Article International Communications in Heat and Mass Transfer ; Volume 130 , 2022 ; 07351933 (ISSN) ; Merdasi, A ; Moosavi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The dynamics and heat transfer performance of droplets play an important role in electrowetting systems. Contrary to the growing trend towards non-Newtonian fluids in electrotechnical systems, most researchers have focused on Newtonian fluids. In the current study, the interface is tracked by the phase-field method and afterwards, the numerical model is confirmed by comparing the results obtained from previous experimental and theoretical works. Several parameters such as power-law index and contact angle are analyzed. Furthermore, the dynamics and heat transfer of the droplets on chemically or topographically structured substrates in the presence of electrowetting are examined. It has been...