Chapter 8 - Methods for calculating the viscosity of hydrocarbons

Abstract

This chapter discusses theoretical, semi-empirical, and empirical methods for calculating the viscosity of a rarefied gas. It notes the advances made in theoretical calculations using ab initio potentials, and the existing problems and ways to solve them. A brief review of theoretical, semi-empirical, and empirical methods for calculating viscosity in a wide range of state parameters is presented, including the viscosity of gases of moderate density and the viscosity of compressed gases and liquids. Among the empirical methods, main attention is paid to methods developed within the framework of various versions of the similarity theory and providing predictive calculation of viscosity in the liquid and gas phases, including the saturation line. A modern approach to describing viscosity in the critical region, based on dynamic scaling theory and the crossover equation, is also considered. A separate section is devoted to the development of interpolation equations that have a theoretically substantiated structure with empirical coefficients obtained by processing the most reliable experimental data on viscosity in a wide range of state parameters. This chapter presents equations published in the literature and developed by the authors based on their own and literature data.