Characterization of macromixing and micromixing performance of unbaffled U-shaped mesoscale oscillatory flow reactor

Abstract

BackgroundUnbaffled U-shaped mesoscale oscillatory flow reactors (meso‑OFRs) are able to achieve low pressure drop, good plug flow and micromixing performance simultaneously at laminar net flow conditions under a wide ‘‘operating windows”. MethodWe focus on the macromixing and micromixing behaviours of unbaffled meso‑OFR, where the net flow and oscillation conditions were in the wide range of Ren=17–51 and Reo=16–1350, respectively. Significant findingsThe good plug flow and micromixing performance could be achieved simultaneously at low oscillation intensity with the wide ‘‘operating windows” of ψ<47. It was believed that oscillatory motion led to periodic destruction and reformation of vortices, as the oscillation intensity increased, the large-scale vortices were decomposed into small-scale vortices, resulting in backmixing or axial dispersion. Meanwhile, the empirical formula of micromixing time and velocity ratio in accordance with the power-law relationship was established:tm/t¯=0.00277ψ0.51658. Finally, the oscillatory mechanism was qualitatively validated by Computational Fluid Dynamics (CFD).