Adiabatic two-phase pressure drop of refrigerants in small channels

Brandon S. Field, Pega Hrnjak

Research output: Contribution to journalArticlepeer-review


The adiabatic pressure drop of two-phase refrigerant flow in small channels has been investigated. A rectangular channel with dh = 148.0 m has been tested with four refrigerants: R134a, R410A, propane (R290), and ammonia (R717). These data have been combined with data taken from five different channels, with dh varying from 70 m to 305 m, of R134a. The measured pressure drops have been compared to many published separated-flow and homogeneous pressure drop models. A new correlation for C, the Chisholm parameter, has been developed based on the Reynolds number of the vapor phase (which contains the majority of the kinetic energy) and the dimensionless grouping - a ratio of viscous to surface tension effects taken from the analysis of capillary flow performed by Sou and Griffith (1964). This allows the new correlation to account for the varying fluid properties (including surface tension) that are found in the different refrigerants. The new correlation takes flow regime into account by means of a Weber number based flow transition criteria, following the flow map of Akbar et al. (2003).

Original languageEnglish (US)
Pages (from-to)704-712
Number of pages9
JournalHeat Transfer Engineering
Issue number8-9
StatePublished - Aug 2007

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


Dive into the research topics of 'Adiabatic two-phase pressure drop of refrigerants in small channels'. Together they form a unique fingerprint.

Cite this