Mixing evaluation of a passive scaled-up serpentine micromixer with slanted grooves

Kristina J. Cook, Yan Feng Fan, Ibrahim Hassan

Research output: Contribution to journalArticle

21 Citations (Scopus)


A novel, passive, scaled-up micromixer based on fluid rotation is proposed and evaluated experimentally and numerically over Reynolds numbers ranging from 0.5 to 100. Flow visualization is employed to qualitatively assess flow patterns, while induced fluorescence is used to quantify species distribution at five locations along the channel length. Two individual fluids are supplied to the test section via a Y-inlet. The fluid enters a meandering channel with four semicircular portions, each of which is lined with nine slanted grooves at the bottom surface. The main mixing channel is 3 mm wide and 0.75 mm deep, with a total length of 155.8 mm. Numerical simulations confirm rotation at all investigated Reynolds numbers, and the strength of rotation increases with increasing Reynolds number. Grooves are employed to promote helical flow, while the serpentine channel structure results in the formation of Dean vortices at Re ≥ 50 (Dean number ≥ 18.25), where momentum has a more significant effect. A decreasing-increasing trend in the degree of mixing was noted, with an inflection point at Re = 5, marking the transition from diffusion dominance to advection dominance. The increase in interfacial surface area is credited with the improved mixing in the advection-dominant regime, while high residence time allowed for significant mass diffusion in the diffusion-dominant regime. Good mixing was achieved at both high and low Reynolds numbers, with a maximum mixing index of 0.90 at Re = 100.

Original languageEnglish
Article number081102
JournalJournal of Fluids Engineering, Transactions of the ASME
Issue number8
Publication statusPublished - 2 Dec 2013



  • Dean vortex
  • Flow visualization
  • Induced fluorescence
  • Micromixer
  • Numerical simulation
  • Rotation
  • Serpentine
  • Slanted grooves

ASJC Scopus subject areas

  • Mechanical Engineering

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