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Rheology Effects on Reaction-diffusion Mechanisms in a Y-shaped Micro Fluidic Mixer

Hellisaz, Hamed | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48882 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Saeedi, Mohammad Hassan; Kazemzadeh Hannani, Siamak
  7. Abstract:
  8. Numerous applications of Lab on a Chips (LOCs) in chemical/biochemical analyses as well as the emergence of advanced methods for their manufacture attracts many researchers’ attention to these micro instruments. Low sample volume consumption and their high controllability are accounted as the main advantage of LOC systems. Micromixers are among the main components of any LOC in which mixing and/or reaction among two components occur. Micromixers have many potential applications in biological and medical sciences, and so they are repeatedly charged by biofluids. Due to sensibility of biofluids, to avoid disintegration, applying electroosmotic flow instead of pressure-induced flow has priority reminding the fact that it can generate more uniform velocity field. Moreover, since complex rheological behavior of biofluids cannot be predicted by Newtonian’s law, an appropriate non-Newtonian rheological model should be invoked. Electroosmotic flow and non-Newtonian rheological model affect reaction-diffusion mechanisms in micromixers significantly, hence investigation of the effects of these factors can be beneficial in design of micromixers. In the current study, a Y-shaped micromixer is investigated: two viscoelastic fluids are injected into the micromixer by simultaneous effects of electroosmotic and pressure gradient forces and a second-order chemical reaction occurs among them. Here, governing equations are solved numerically by applying finite volume method and using non-uniform mesh structure. In addition, an analytical solution for the special case of no chemical reaction is also suggested. Results show that fivefold increase of fluid elasticity decreases chemical reaction production up to 65 percent. What’s more, increase of fluid elasticity is shown to decrease dispersion of production through microchannel and augment production around center. It is also shown that effect of rheology on system is dependent on electrical double layer (EDL) and direction of pressure gradient (favorable or unfavorable to electroosmotic flow)
  9. Keywords:
  10. Electroosmotic Flow ; Viscoelastic Fluids ; Micromixer ; Lab-on-a-Chip ; Numerical Solution ; Numerical Modeling ; Rheology

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  • 3D modeling of reaction-diffusion dynamics in an electrokinetic Y-shaped microreactor
    • 1 Introduction
    • 2 Problem formulation
      • 2.1 Problem definition
      • 2.2 Electrical potential distribution
      • 2.3 Velocity distribution
      • 2.4 Mass transport equation
    • 3 Numerical method
    • 4 Method validation
    • 5 Results and discussion
      • 5.1 Transverse distribution of production
      • 5.2 Production concentration layer
      • 5.3 Production efficiency
    • 6 Conclusions
    • Acknowledgment
    • Appendix A
    • References
  • Biographies
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