The viscosity of R32 and R125 at saturation

Abstract

This paper reports new measurements of the viscosity of R32 and R125, in both the liquid and the vapor phase, over the temperature range 220 to 343 K near the saturation line. The measurements in both liquid and vapor phases have been carried out with a vibrating-wire viscometer calibrated with respect to standard reference values of viscosity. It is estimated that the uncertainty of the present viscosity data is one of 0.5-1%, being limited partly by the accuracy of the available density data. The experimental data have been represented by polynomial functions of temperature for the purposes of interpolation.

Viscosity of Difluoromethane and Pentafluoroethane along the Saturation Line

“…The results for liquid HFC-32 along the saturation line deviate from eq 14 with a maximum deviation of about 0.9%. The results of Oliveira and Wakeham (1993) are very close to our values with average deviations from eq 14 within 1% and the greatest deviation being about 2%. The deviations of the values of Ripple and Martar (1993) and from eq 14 remain within 5%.…”

“…A mixture of difluoromethane (HFC-32) and pentafluoroethane (HFC-125) is a potential alternative to replace chlorodifluoromethane . The viscosity of HFC-32 was measured by Oliveira and Wakeham (1993), Ripple and Martar (1993), , and Phillips and Murphy (1970). The viscosity of HFC-125 was measured by Diller and Peterson (1993), Ripple and Martar (1993), Oliveira and Wakeham (1993), and .…”

“…The viscosity of HFC-32 was measured by Oliveira and Wakeham (1993), Ripple and Martar (1993), , and Phillips and Murphy (1970). The viscosity of HFC-125 was measured by Diller and Peterson (1993), Ripple and Martar (1993), Oliveira and Wakeham (1993), and . The differences between the results from different authors is considerable, sometimes in excess of 10%.…”

Surface Tension and Liquid Viscosity of R32+R1234yf and R32+R1234ze

“…Their data agree well with our results with the maximum deviation of 3.05, 5.13, and 2%, respectively. Oliveira et al 40 obtained the experimental data using vibrating-wire viscometer with an estimated uncertainty of 0.5∼1, and 0.5%, respectively. Their data are consistent with our results except for the viscosity at 343.14 K (T r = 0.977) by Oliveira, which a deviation larger than 12% can be found and might be due to the measurement being taken in the proximity of the critical point and the larger uncertainty of the density data.…”

Dynamic viscosity measurements by photon correlation spectroscopy

“…The diffusion coefficient is obtained by evaluating the time-dependent homodyne autocorrelation function ~,"-'( t ) = a + I, exp(t/r~ ) (2) with experimental constants a and h for the decay time r,. and with…”