International Journal

Boiling flow patterns and dry-out characteristics of R-1234ze(E) in a plate heat exchanger
Year of publication 2020
Title of paper Boiling flow patterns and dry-out characteristics of R-1234ze(E) in a plate heat exchanger
Author DongChan Lee, ChangUk Jo, Byeongsu Kim, Yongchan Kim
Publication in journal International Journal of Heat and Mass Transfer
Publication date 8 August 2020
Volume & other data Volume 161, 120308
Abstract In this study, boiling flow patterns and dry-out characteristics of R-1234ze(E) in a plate heat exchanger (PHE) are investigated through visualizations and surface temperature measurements. The boiling flow patterns in the PHE are classified into three regimes by reflecting an evident flow direction and inter- mittent flooding (IF): rough liquid film flow, pulsating annular flow, and steady annular flow. Boiling mechanisms in the liquid-preferred and vapor-preferred paths are analyzed in a single channel. A boiling flow pattern map of R-1234ze(E) in the PHE is developed in terms of liquid and vapor superficial mo- mentums, and the criteria for the transitions of the flow regimes are proposed to provide a reference for predicting flow characteristics during phase changes. Based on the measured surface temperatures, the partial dry-out is observed at medium to high vapor qualities in the center of the vapor-preferred path owing to the lack of the liquid phase. In addition, the relationships between the IF, partial dry-out, and heat transfer coefficients are comprehensively analyzed with physical interpretations.
Keywords Flow pattern, Dry-out, Plate heat exchanger, Flow visualization, Low gwp
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