Falling film evaporation of R410A outside horizontal single tubes and a tube bundle

P. H. Jin, C. Y. Zhao, J. X. Liu, W. T. Ji, W. Q. Tao*

*Corresponding author for this work

Research output: Chapter in Book or Report/Conference proceedingConference Proceedingpeer-review

Abstract

This study investigated falling film heat transfer characteristics of mixture refrigerant R410A on horizontal copper tubes. A horizontal plain tube, an enhanced boiling tube and a triangular-pitch tube bundle comprised of 6 commercial boiling tubes were tested. Major results are as follows. For both plain and enhanced tubes, the effect of film Reynolds number on heat transfer coefficients is negligible at high film Reynolds number. As Reynolds number decreases to a certain value, heat transfer coefficients decrease sharply due to the occurrence of partial dryout on the outer surfaces. At the same saturation temperature, heat transfer coefficients increase with heat flux. At higher heat fluxes, the film flow rate below which dryout occurs and the related threshold film Reynolds number becomes larger. Heat transfer coefficients of the enhanced tubes are obviously higher than the plain tube. Effect of saturation temperature on heat transfer coefficients differs with heat flux. In the tube bundle, heat transfer deteriorates earlier for the tubes positioned at the lower part of the bundle due to insufficient film flow rate. Tubes of the middle column of the three columns own higher heat transfer coefficients. It is found out that for R410A, the smooth tube performs better compared with R134a while worse or comparable for the enhanced boiling tube. Heat transfer coefficients of the plain tube can be reasonably predicted by the empirical correlation of Zhao et al [14].

Original languageEnglish
Title of host publicationProceedings of the 2nd Thermal and Fluid Engineering Summer Conference, TFESC 2017 and 4th International Workshop on Heat Transfer, IWHT 2017
PublisherBegell House Inc.
Pages2883-2897
Number of pages15
ISBN (Electronic)9781567004700
Publication statusPublished - 2017
Externally publishedYes
Event2nd Thermal and Fluid Engineering Summer Conference, TFESC 2017 and 4th International Workshop on Heat Transfer, IWHT 2017 - Las Vegas, United States
Duration: 2 Apr 20175 Apr 2017

Publication series

NameProceedings of the Thermal and Fluids Engineering Summer Conference
Volume2017-April
ISSN (Electronic)2379-1748

Conference

Conference2nd Thermal and Fluid Engineering Summer Conference, TFESC 2017 and 4th International Workshop on Heat Transfer, IWHT 2017
Country/TerritoryUnited States
CityLas Vegas
Period2/04/175/04/17

Keywords

  • Enhanced tube
  • Falling film evaporation
  • Mixture refrigerant
  • Plain tube
  • Tube bundle

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