MEASUREMENTS OF THE VISCOSITY OF R11, R12, R141B, AND R152A IN THE TEMPERATURE-RANGE 270-340-K AT PRESSURES UP TO 20-MPA

This paper reports new measurements of the liquid viscosity of R11, R1 2, R141b, and R152a in the temperature range 270 to 340 K and pressure s up to 20 MPa. The measurements have been carried out in a vibrating- wire instrument calibrated with respect to the standard reference valu e of the viscosity of water. It is estimated that the uncertainty of t he present viscosity data is one of 0.5%. The experimental data have b een represented by polynomial functions of temperature and pressure fo r the purposes of interpolation. A recently developed semiempirical sc heme, based on considerations of hard-sphere theory, is employed to co rrelate successfully the viscosity and the thermal conductivity of the se refrigerants as a function of their density.