Convective boiling heat transfer characteristics of CO2 in microchannels

Rin Yun, Yongchan Kim, Min Soo Kim

Research output: Contribution to journalArticlepeer-review

103 Citations (Scopus)


Convective boiling heat transfer coefficients and dryout phenomena of CO2 are investigated in rectangular microchannels whose hydraulic diameters range from 1.08 to 1.54 mm. The tests are conducted by varying the mass flux of CO2 from 200 to 400kg/m2s, heat flux from 10 to 20kW/m2, while maintaining saturation temperature at 0, 5 and 10°C. Test results show that the average heat transfer coefficient of CO2 is 53% higher than that of R134a. The effects of heat flux on the heat transfer coefficient are much significant than those of mass flux. As the mass flux increases, dryout becomes more pronounced. As the hydraulic diameter decreases from 1.54 to 1.27mm and from 1.27 to 1.08 mm at a heat flux of 15kW/m2 and a mass flux of 300kg/m2s, the heat transfer coefficients increase by 5% and 31%, respectively. Based on the comparison of the data from the existing models with the present data, the Cooper model and the Gorenflo model yield relatively good predictions of the measured data with mean deviations between predicted and measured data of 21.7% and 21.2%, respectively.

Original languageEnglish
Pages (from-to)235-242
Number of pages8
JournalInternational Journal of Heat and Mass Transfer
Issue number2
Publication statusPublished - 2005 Jan


  • Boiling heat transfer
  • CO
  • Heat transfer coefficient
  • Microchannel heat exchanger
  • Microchannels

ASJC Scopus subject areas

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


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