Geometrical Effects on Fluid Mixing of Pulsatile Flow in Convergent-Divergent Micromixer

Time-dependent pulsatile flows have been used by many researchers for fast and efficient mixing at micro-scale [1–2]. In a recent study, a convergent-divergent microchannel with sinusoidal walls showed a strong coupling with pulsatile flow for enhanced mixing performance over a short mixing length [3]. In the present study, effects of two geometrical parameters, i.e., the ratio of amplitude to wavelength and ratio of throat-width to depth on mixing performance, were analyzed with the Strouhal number and the ratio of pulsing amplitude to steady flow velocity at a fixed Reynolds number, Re = 0.5. The flow and mixing analyses were performed using unsteady Navier-Stokes equations and a diffusion-convection model for species concentration.