서강대학교

초록/요약

The study on diffusion/electrodiffusion phenomena has contributed to the development of miniaturized systems like μTas or LOC. Miniaturization of device can lead to performance improvements. It also enables easy integration into another system because of its small size. Particle dispersion is a fundamental issue in microfluidic system. It refers to inevitable spreading along the flow direction of dissolved or suspended Brownian particles. From the point of view, diffusion/electrodiffusion phenomena are worth to study on. Thereby, this thesis comprises two parts: diffusion phenomena and electrodiffusion phenomena. In the first, the part for diffusion phenomena is presented, focused on Taylor dispersion using Brownian dynamics and computational fluid dynamics. To validate the numerical model, one-dimensional simulation is performed and compared with the theoretical solution. After confirming that the validation model has a good accuracy, three-dimensional rectangular cross-sectional model is calculated by Brownian dynamics. In addition to Brownian dynamics, computational fluid dynamics simulation is performed at the same three-dimensional system again. Finally, these two simulation results are compared with the theoretical solution of Taylor-aris and pure convection regions. At the second part, calculations related with electrodiffusion are introduced. Similarly to the part for diffusion phenomena, the numerical model is validated before the simulation of main model. Three-dimensional capillary tube is chosen to validation system. Velocity profile is matched up with the theoretical solution named Helmholtz-Smolouchowski relation. After confirming that the validation model shows a good agreement with the solution, three-dimensional micro/nano- channel model is calculated. As a result of simulation, several interesting features are observed especially around the nanochannel in terms of ion concentration, electric potential, and electric field.