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Numerical modeling of surface reaction kinetics in electrokinetically actuated microfluidic devices

Sadeghi, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.aca.2014.05.023
  3. Abstract:
  4. We outline a comprehensive numerical procedure for modeling of species transport and surface reaction kinetics in electrokinetically actuated microfluidic devices of rectangular cross section. Our results confirm the findings of previous simplified approaches that a concentration wave is created for sufficiently long microreactors. An analytical solution, developed for the wave propagation speed, shows that, when normalizing with the fluid mean velocity, it becomes a function of three parameters comprising the channel aspect ratio, the relative adsorption capacity, and the kinetic equilibrium constant. Our studies also reveal that the reactor geometry idealized as a slit, instead of a rectangular shape, gives rise to the underestimation of the saturation time. The extent of this underestimation increases by increasing the Damkohler number or decreasing the dimensionless Debye-Hückel parameter. Moreover, increasing the values of the Damkohler number, the dimensionless Debye-Hückel parameter, the relative adsorption capacity, and the velocity scale ratio results in lower saturation times
  5. Keywords:
  6. Mass transport ; Surface reaction ; Aspect ratio ; Association reactions ; Equilibrium constants ; Fluidic devices ; Mass transfer ; Numerical models ; Surface reactions ; Wave propagation ; Adsorption capacities ; Channel aspect ratios ; Concentration waves ; Electroosmotic flow ; Micro-fluidic devices ; Model of surface reaction ; Numerical procedures ; Rectangular cross-sections ; Kinetics ; Adsorption kinetics ; Chemical engineering ; Chemical reaction kinetics ; Computational fluid dynamics ; Concentration (parameters) ; Damkohler number ; Debye Huckel parameter ; Electroosmosis ; Equilibrium constant ; Geometry ; Mathematical model ; Microfluidics ; Numerical modeling ; Priority journal ; Relative adsorption capacity ; Velocity scale ratio
  7. Source: Analytica Chimica Acta ; Vol. 838, issue , August , 2014 , pp. 64-75 ; ISSN: 00032670
  8. URL: http://www.sciencedirect.com/science/article/pii/S0003267014006163