New correlations between viscosity and surface tension for saturated normal fluids

New correlations between viscosity and surface tension are proposed and checked for saturated normal fluids. The proposed correlations contain three or four adjustable coefficients for every fluid. They were obtained by fitting 200 data points, ranging from the triple point to a point very near to the critical one. Forty substances were considered, including simple fluids (such as rare gases), simple hydrocarbons, refrigerants, and some other substances such as carbon dioxide and water. Two correlation models with three adjustable coefficients were checked, and the results showed that the one based on the modified Pelofsky expression gives the better overall results. A new 4-coefficient correlation is then proposed which clearly improves the results, giving the lowest overall deviations for 32 out of the 40 substances considered and absolute average deviations below 10% for all of them.