TJ831 : Numerical investigation and validation of the generation of induced vortices on floating electrodes in order to separate particles inside a microchip
Thesis > Central Library of Shahrood University > Mechanical Engineering > MSc > 2022
Authors:
[Author], Mohammad Mohsen Shahmardan[Supervisor], Mohsen Nazari[Supervisor]
Abstarct: Numerical Investigation validation of generating induced vortices around float electrodes for particle –partitioning in a microchip In this research, using electrokinetic method, which acts as a technique for conducting fluids and particles, an attempt has been made to design a microchip baxsed on numerical results obtained through Camsol software, which has the best performance in separating and guiding target particles in one direction. In this microchannel, a floating electrode is placed on the floor, between two other electrodes that are connected to a voltage source. There are also several other electrodes at the beginning of the channel on the floor and ceiling of the microchannel with the aim of being able to place the particles in a specified path before reaching the floating electrode. In this method, when a surface is immersed in an electrolyte solution and subjected to an electric field, that surface is immediately polarized, with one part of the surface having a negative charge and the other part of that surface having a positive charge. The particles in the solution are each adsorbed to a portion of the surface. The electrokinetics of the induced charge, which describes the flow of a fluid on a solid surface of a polarizable conductor and the motion of particles in an electric field, has received increasing attention and generates an electrically induced double laxyer of nonlinear zeta potential. On a solid surface, the motion of the particles is due to the force of electrophoresis, and the effective slip velocity on the surface is linearly proportional to the applied electric field. This linear relationship leads to a slow velocity, resulting in a smooth flow. The electric field used interacts with the electric double laxyer, which leads to the generating of induced electroosmosis. When induced electroosmosis occurs around an asymmetric particle, the particle moves through it. The induced electroosmosis rate is faster than conventional electroosmosis generated on a nonconducting solid surface and is therefore capable of producing vortices. The particles were able to deflect through the resulting vortices to the sub-channel located on the ceiling of the microchannel in the area of the floating electrode. In this way, we were able to separate the particles and conduct them with high efficiency. In this study, the better performance of induced electromosmosis and the role of voltage and velocity in particle separation and conduction are shown. Placing the sub-channel and the electrodes at the beginning of the channel in this microchannel is an innovation in its initial design so that it can simultaneously collect the target particles in a specific place in addition to guiding them. In the simulation results, it was observed that for the input velocities (150-1200 μm / s), respectively, with the applied voltages (V10-33) (to the left of the floating electrode electrode), 100% of the particles can be directed and separated to the sub-channel. Separation in the range of speeds mentioned and without applying voltage is equal to 10% of the particles. To confirm the simulation results, an experimental results was performed with a speed of 1200 μm / s and a voltage of 33 V, which, similar to what was observed in the simulation, 100% of the microparticles were directed to the sub-channel. This separation of particles in a fluid is used to achieve goals that are used in various fields of science, including medical diagnosis and blood analysis and experiments to determine the amount of useful and useless particles in water.
Keywords:
#Keywords: Electrokinetics #Electroosmosis #Induction charge #Floating electrodes #ICEK vortexes #Particle separation Keeping place: Central Library of Shahrood University
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