Numerical simulation of gas-liquid two-phase flow and convective heat transfer in a micro tube

Koji Fukagata, Nobuhide Kasagi, Poychat Ua-arayaporn, Takehiro Himeno

Research output: Contribution to journalArticlepeer-review

98 Citations (Scopus)


Numerical simulation of an air and water two-phase flow in a 20 μm ID tube is carried out. A focus is laid upon the flow and heat transfer characteristics in bubble-train flows. An axisymmetric two-dimensional flow is assumed. The finite difference method is used to solve the governing equations, while the level set method is adopted for capturing the interface of gas and liquid. In each simulation, the mean pressure gradient and the wall heat flux are kept constant. The simulation is repeated under different conditions of pressure gradient and void fraction. The superficial Reynolds numbers of gas and liquid phases studied are 0.34-13 and 16-490, respectively, and the capillary number is 0.0087-0.27. Regardless of the flow conditions, the gas-phase velocity is found approximately 1.2 times higher than the liquid-phase velocity. This is in accordance with the Armand correlation valid for two-phase flows in macro-sized tubes. The two-phase friction coefficient is found to be scaled with the Reynolds number based on the effective viscosity of the Einstein type. The computed wall temperature distribution is qualitatively similar to that observed experimentally in a mini channel. The local Nusselt number beneath the bubble is found notably higher than that of single-phase flow.

Original languageEnglish
Pages (from-to)72-82
Number of pages11
JournalInternational Journal of Heat and Fluid Flow
Issue number1 SPEC. ISS.
Publication statusPublished - 2007 Feb
Externally publishedYes


  • Bubble
  • Gas-liquid flow
  • Heat transfer
  • Micro tube
  • Numerical simulation
  • Pressure drop
  • Two-phase flow

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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