Dependence of the viscosity of liquid 3,3-diethylpentane, mercury, argon and methane on thermal pressure over a wide PVT range

Abstract

Specific volumes and viscosities of 3,3-diethylpentane have been measured between 25 and 150°C and up to 8000 bar. Numerical differentiation of the volumetric data gives values of thermal pressure, (∂P/∂T)_V. It is demonstrated that ηV/T^1/2 is a function of (V/R)(∂P/∂T)_V only and based on the premise of a soft-sphere van der Waals model, this is interpreted to indicate a direct connection between viscosity and the temperature derivative of repulsive energy at constant volume. The correlation is tested by application to mercury, argon, methane etc.