Transport Property Measurements on the IUPAC Sample of 1,1,1,2-Tetrafluoroethane (R134a)

This paper reports the results of an iInternational project coordinated by the Subcommittee on Transport Properties of Commission I.2 of the IInternational Union of Pure and Applied Chemistry. The project has been conducted to investigate the large discrepancies between the results reported by various authors for the transport properties of R134a and culminates the effort which was initially described in 1995. The project has involved the remeasurement of the transport properties of a single sample of R134a in nine laboratories throughout the world in order to test the hypothesis that at least part of the dis- crepancy could be attributed to the purity of the samples. This paper provides an iIntercomparison of the new experimental results obtained for the viscosity 1 0195-928X 00 0100-0001 18.00 0 2000 Plenum Publishing Corporation 1 Department of Chemical Engineering, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece. 2 Lehrstuhl fu r Technische Thermodynamik, Friedrich-Alexander Universita t Erlangen- Nu rnberg, Am Weichselgarten 8, D-91058 Erlangen, Germany. 3 Institute for Environmental Research and Technology, National Research Council of Canada, Ottawa K1A 0R6, Canada. 4 Department of System Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. 5 Departamento de Qu@ mica e Bioqu@ mica and Centro de Cie^ncia e Moleculares de Materiais, Faculdade de Cie^ncias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal. 6 Physical and Chemical Properties Division, National Institute of Standards and Technol- ogy, 325 Broadway, Boulder, Colorado 80303, U.S.A. 7 Department of Chemical Engineering, Chalmers University of Technology, S-41296 Gothenburg, Sweden. 8 Fachbereich Chemie, Universita t Rostock, D-18051 Rostock, Germany. 9 Department of Chemical Engineering and Chemical Technology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BY, United Kingdom. 10 To whom correspondence should be addressed. and thermal conductivity in the vapor, liquid, and supercritical gas phases. The viscosity measurements were made with a variety of techniques including the vibrating wire, oscillating disk, capillary flow, and falling body. Thermal con- ductivity was measured using transient bare and anodized hot wires, steady- state anodized hot wires, and light scattering. Agreement between a variety of experimental techniques using the standard round-robin sample is necessary to demonstrate that some of the discrepancies in earlier results were due to sample impurities. Identification of disagreement between data using one experimental technique relative to other techniques may suggest modifications that would lead to more accurate measurements on these highly polar refrigerant materials. It is anticipated that the new data which have been measured on this IUPAC round-robin sample will aid in the identification of the reliable data sets in the literature and ultimately allow the refinement of the IUPAC reference-data correlations for the transport properties of R134a.