Approximate Theory of Viscosity and Thermal Conductivity in Dense Polyatomic Fluids

Abstract

Formulas are derived for the collisional contributions to the pressure tensor and heat‐flux vector in fluids composed of molecules which interact with impulsive forces. An approximation scheme is then employed to obtain ``zero‐order'' estimates of the viscosity and thermal conductivity coefficients for various molecular models. The models considered are rough spherical and rigid convex molecular ``cores'' surrounded by potential staircases. The viscosity and thermal conductivity coefficients determined for the special case of cores surrounded by a square‐well attractive potential are found to vary approximately as T^1/2 e^A/T at ordinary liquid temperatures. Calculations are also presented of the variations of the transport coefficients with molecular shape and eccentricity parameters.