Abstract
A simple viscosity correlation over a wide region (0.33_??_Vr_??_100, Tb<T<Tc, 0.1 MPa < P<Pc) is proposed. This correlation contains four parameters and their optimum values for 22 substances were determined from reference data. Among the four determined parameters, a molecular size parameter was correlated with liquid volume at normal boiling point. Two parameters of the remaining three were fixed as constants for three substance groups : inorganics, hydrocarbons and fluorocarbons. Thus, the proposed correlation became a one-parameter viscosity correlation. In viscosity calculation, averages of root mean square of deviations (RMS) of the proposed one were, respectively, 6.84 % and 6.96 % for vapor and liquid regions. Since RMS of Jossi-Stiel-Thodos' correlation was too large (22.87 %) in the liquid region, the deviation of liquid viscosity of the proposed correlation was compared with the other three for liquid viscosity. As a result, the deviation of the proposed correlation was comparable to that of Ototake and was superior to that of Li-Poole and Goletz-Tassious.
