Numerical investigation of near-critical fluid convective flow mixing in microchannels

Lin Chen, Xin Rong Zhang, Junnosuke Okajima, Shigenao Maruyama

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


Supercritical CO2 fluid has been widely used in chemical extraction, chemical synthesis, micro-manufacturing and heat transfer apparatus, and so forth. The current study deals with near-critical CO2 microchannel mixing flow and its basic characteristics. Careful numerical investigations are carried out by solving the coupled computational fluid dynamic equations. The results show that strong near-critical vortex flows can be achieved in a relatively wide range of initial and controlling conditions in microchannels. Basic, isothermally developed flows are simulated and then used as the initial state for a heat convective simulation. After the wall heat flux is applied, the vortex mixing flow originates from the hot boundaries in microchannels with height D=100μm to 200μm, while natural convection will gradually become dominant for microchannels with D=300μm to 500μm. The current micro-mixing evolution can be ascribed to a novel type of Kelvin-Helmholtz instability. Well-correlated characteristic numbers are identified for the effective near-critical microchannel mixing cases. The vortex growth and evolution mode in microchannels are found to differ greatly from previous micro-mixing methods. Possible applications in micro-engineering/chemical process are also discussed in this study.

Original languageEnglish
Pages (from-to)67-80
Number of pages14
JournalChemical Engineering Science
Publication statusPublished - 2013 Jun 28


  • Fluid mechanics
  • Microchannel
  • Mixing
  • Near-critical fluid
  • Numerical analysis
  • Thermodynamics process

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering


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