Mesurage de la fraction de vide et visualisation des régimes d’écoulement de R134a dans des tubes circulaires horizontaux et verticaux d'un diamètre intérieur de 7mm

Translated title of the contribution: Void fraction measurement and flow regimes visualization of R134a in horizontal and vertical ID 7 mm circular tubes

Hongliang Qian, Pega Hrnjak

Research output: Contribution to journalArticle

Abstract

Flow regimes and void fraction in horizontal and vertical round smooth tubes ID 7 mm with R134a in the adiabatic conditions (saturation temperature at 33 °C) and low mass flux (40–150 kg/m2 s for horizontal tubes and 65–115 kg/m2 s for vertical tubes) are presented in this paper. Flow regimes are captured by a high-speed camera while void fraction is measured by quick-closing valve method. The horizontal flow patterns are compared to Wojtan et al. (2005a) flow-regime map and some modifications based on visualization results are proposed. Void fraction results for both horizontal and vertical flows are compared to some widely used correlations. Influences of tube orientation and mass flux on void fraction are discussed. When the vapor quality keeps constant, void fraction of horizontal tubes is larger than that of vertical tubes. Higher mass flux also results in larger void fraction compared that of lower mass flux.

Translated title of the contributionVoid fraction measurement and flow regimes visualization of R134a in horizontal and vertical ID 7 mm circular tubes
Original languageFrench
Pages (from-to)191-203
Number of pages13
JournalInternational Journal of Refrigeration
Volume103
DOIs
StatePublished - Jul 2019

Keywords

  • Flow regimes
  • High-speed camera
  • Quick-closing valves
  • R134a
  • Smooth tube
  • Void fraction

ASJC Scopus subject areas

  • Building and Construction
  • Mechanical Engineering

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