Flow patterns and pressure drop of vertical upward flows in a tube with header-like protrusions with R134a

Hongliang Qian, Pega Hrnjak

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


Flow patterns and pressure drop in a vertical tube with header-like protrusions in adiabatic conditions are presented. Three major flow patterns are observed with a high-speed camera in the mass flow rate range studied in this paper: slug flow, churn flow and annular flow. The flow pattern map is proposed. As the distance between two measurement ports along the tube decreases, pressure drop of refrigerant flows in the tube with protrusions decreases for all vapor qualities and mass flow rates. The relation is close to linear. However, the relation between pressure drop between two certain ports and quality is not linear. For relatively larger mass flow rate, as the quality increases from 0, pressure drop decreases first and then increases. There is a smallest pressure drop at moderate quality. The smallest pressure drop among all the qualities between two certain ports happens decrease from x=1 to x=0.6 as mass flow rate increase from 3 g/s to 7.5 g/s. If the quality is kept to be constant, DP is smaller for higher mass flow rate for relatively small qualities. However, in the high-quality range, DP is larger for higher mass flow rate.

Original languageEnglish (US)
Title of host publicationICR 2019 - 25th IIR International Congress of Refrigeration
EditorsVasile Minea
PublisherInternational Institute of Refrigeration
Number of pages8
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


  • Pressure drop
  • R134a
  • Refrigerant
  • Vertical flow

ASJC Scopus subject areas

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


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