Flow patterns and heat transfer characteristics of R-1234ze(E) for downward condensation in a plate heat exchanger

Dong Chan Lee, Sungho Yun, Jun Young Choi, Yongchan Kim

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


This study investigates the condensation flow patterns and heat transfer characteristics of a low global warming potential refrigerant R-1234ze(E) for downward flow in a plate heat exchanger through flow visualization. An asymmetric flow aspect for downward condensation is characterized by vapor- and liquid-preferred paths owing to the effect of gravity. Flow patterns for downward condensation are classified into two regimes: steady film flow without intermittent flooding and pulsating film flow involving intermittent flooding. Additionally, the condensation heat transfer coefficient and frictional pressure drop were analyzed considering flow patterns. Intermittent flooding is hardly related to the heat transfer performance. A frequency analysis of the pressure drop exhibited a considerable difference in periodic characteristics between the flow regimes with and without intermittent flooding. Finally, the visualization data coincided with the flow pattern map proposed by the existing study, and an empirical correlation for predicting the flow transition between pulsating and steady film flow was developed in terms of the Weber number.

Original languageEnglish
Article number121373
JournalInternational Journal of Heat and Mass Transfer
Publication statusPublished - 2021 Aug

Bibliographical note

Funding Information:
This work was jointly supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy ( MOTIE ) of the Republic of Korea (No. 20208901010010 ) and the Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 20HSCT-B157909-02 ).

Publisher Copyright:
© 2021


  • Condensation
  • Flow pattern
  • Low GWP
  • Plate heat exchanger
  • R-1234ze(E)

ASJC Scopus subject areas

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


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