Characterization of two-phase flow distribution in microchannel heat exchanger header for air-conditioning system

Mark Anthony Redo*, Jongsoo Jeong, Niccolo Giannetti, Koji Enoki, Seiichi Yamaguchi, Kiyoshi Saito, Hyunyoung Kim

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


The two-phase flow distribution behavior of R410A within the vertical header of a microchannel heat exchanger with multiple horizontally oriented microchannel flat tubes was investigated and is reported in this paper. Unlike most previous studies, which examined the distribution at lower flowrates applicable mostly to automobile applications, this work evaluated higher flowrates relevant to actual air conditioning evaporator applications with larger size headers. The following operating conditions, were utilized: an inlet mass flowrate that varied from 40 to 200 kg h−1 (mass flux of 27–250 kg m−2 s−1 in the header), vapor qualities of 0.1, 0.2, and 0.6, and evaporating temperatures of 10 and 15 °C. The tube protrusion depth into the header was set at 0 and 50%. Flow distribution profiles derived from the experiment measurements and clear visualization images captured by a high speed camera showed that the distribution improves for increased inlet mass flux at low vapor quality, while a 5 °C difference in evaporating temperature does not yield a substantial distribution change. A 50% protrusion produces higher inertial forces pushing the liquid level towards the top section. A correlation was developed to predict the liquid distribution by relating the portion of liquid exiting the branch tube to the liquid at the immediate header as a function of the liquid Froude number.

Original languageEnglish
Pages (from-to)183-193
Number of pages11
JournalExperimental Thermal and Fluid Science
Publication statusPublished - 2019 Sept


  • Correlation
  • Experiment
  • Flow distribution
  • Microchannel heat exchanger
  • Two-phase flow
  • Vertical header
  • Visualization

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Nuclear Energy and Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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