Analysis and quantification of generated bubbles for flow boiling through diabatic visualization

Cheng Min Yang, Pega Hrnjak

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper aims at presenting the heat transfer analysis of flow boiling in horizontal smooth and micro-finned tubes through visualization in diabatic conditions. Visualization of R410A flow boiling experiments were conducted in a transparent concentric heat exchanger. 3D printed clear resin tubes with different geometries are placed in an outer glass tube with annular water flow for visualizing the flow during evaporation. Parameters of generated bubble such as departure diameter and frequency are quantified based on visualization using high-speed camera and video processing techniques. Heat transfer in the test section is analyzed through the temperature measurements and estimated bubble parameters. Two regions of incipience of boiling are found in the current experiments. As the superheat is insufficient to reach the onset point of nucleate boiling, the heat transfer is governed by forced convection. At a higher heat flux, the heat transfer is by the mechanisms of the forced convection and surface nucleate boiling.

Original languageEnglish (US)
Title of host publicationICR 2019 - 25th IIR International Congress of Refrigeration
EditorsVasile Minea
PublisherInternational Institute of Refrigeration
Number of pages7
ISBN (Electronic)9782362150357
StatePublished - 2019
Event25th IIR International Congress of Refrigeration, ICR 2019 - Montreal, Canada
Duration: Aug 24 2019Aug 30 2019

Publication series

NameRefrigeration Science and Technology
ISSN (Print)0151-1637


Conference25th IIR International Congress of Refrigeration, ICR 2019


  • 3D printed
  • Diabatic condition
  • Flow boiling
  • Micro-fin
  • Visualization

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Condensed Matter Physics

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