Determination of Second Virial Coefficients and Virial Equations of R-32 (Difluoromethane) and R-125 (Pentafluoroethane) Based on Speed-of-Sound Measurements

T. Hozumi, T. Ichikawa, H. Sato, K. Watanabe

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The second virial coefficients, B, for difluoromethane (R-32, CH2F2) and pentafluoroethane (R-125, CF3CHF2) are derived from speed-of-sound data measured at temperatures from 273 to 343 K with an experimental uncertainty of ±0.0072%. Equations for the second virial coefficients were established, which are valid in the extensive temperature ranges from 200 to 400 K and from 240 to 440 K for R-32 and R-125, respectively. The equations were compared with theoretically derived second virial coefficient values by Yokozeki. A truncated virial equation of state was developed using the determined equation for the virial coefficients. The virial equation of state represents our speed-of-sound data and most of the vapor PρT data measured by deVries and Tillner-Roth within ±0.01 and ±0.1%, respectively.

Original languageEnglish
Pages (from-to)1677-1688
Number of pages12
JournalInternational Journal of Thermophysics
Volume20
Issue number6
DOIs
Publication statusPublished - 1999 Nov

Keywords

  • R-125
  • R-32
  • alternative refrigerant
  • equation of state
  • hydrofluorocarbon
  • second virial coefficient
  • speed of sound

ASJC Scopus subject areas

  • Condensed Matter Physics

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