Abnormal microchannel convective fluid flow near the gas-liquid critical point

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

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


This article deals with a CO2 critical microchannel convective flow with heat applied from two side walls. Fluid near its gas-liquid critical point is very dense and much expandable; meanwhile, the thermal diffusivity tends to zero when it goes near the critical point. In microchannels, the effect of natural convection becomes negligible and the boundary thermal-mechanical effects will dominate the convection and thermal equilibrium processes. We numerically simulate the convection behaviours of near-critical fluids confined in microchannels by solving the Navier-Stokes equations together with conservative equations of mass and energy. Due to the thermal-mechanical effects of critical fluid, abnormal convection-onset structures and transient micro-scale vortex/mixing evolution modes have been found. The thermal-mechanical/acoustic perturbation source identified here contributes to a new type of Kelvin-Helmholtz instability when gravity is suppressed. The thermal-mechanical oscillations in the boundaries serve as the origin of current vortex phenomena from fast boundary expansion and density stratification. The abnormal microchannel vortex evolution and instability mechanisms/threshold are also discussed in detail in this article.

Original languageEnglish
Pages (from-to)10-24
Number of pages15
JournalPhysica A: Statistical Mechanics and its Applications
Publication statusPublished - 2014 Mar 15


  • Carbon dioxide
  • Kelvin-Helmholtz instability
  • Microchannel
  • Near-critical fluids
  • Thermal relaxation


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