Numerical Simulation and Analysis of Active Electro-Kinetic Micro-Mixer

Maleki Bagherabadi, Kamyar | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 49139 (58)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Saeedi, Mohammad Saeed; Sani, Mahdi
  7. Abstract:
  8. The “Lab-on-a-Chip” is a micro-scale device which uses fluids as working medium and can handle number of functions such as sample preparation and transfer, separation, bio-sensing and detection. One of the important parts of these devices is micro-mixer, that should blend two fluid species in a short time with desirable mixing quality. Micro-mixers are classified as passive and active. By considering the micro-scale of mixers, turbulence phenomena cannot occur due to dominance of viscous forces, therefore the mixing only depends on molecular diffusion. This thesis consists of two main parts, in the first part algebraic multigrid has been studied and implemented in Rayan (in-house CFD code). It also contains validation of the performance of the applied algorithms. In the second part, the passive and active micro-mixers have been studied numerically. The main effort in this thesis was the modeling the active mixers by employing electrodes with alternating voltage as mixing actuators. The dominant phenomena in this type of mixers is electro-osmotic flow and instability that has been modeled by PNP-NSE equations. According to the simulations, our final design with mixing electrodes mounted on the vertical wall mixed the streams with 99% mixing efficiency in a mixing time of just 2.7 seconds
  9. Keywords:
  10. Micromixer ; Active Micromixer ; Passive Micro-Mixer ; Electrokinetic Process ; Electroosmotic Flow ; Algebraic Multigrid

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