Transport properties of gases at moderate pressure

The three specific properties - viscosity, thermal conductivity and mass diffusion coefficient - are referred to as transport properties, because they are linked to the agitation of molecules. Molecular transport of momentum, energy and chemical species is the corollary of fluid cohesion forces.

The kinetic theory of gases makes it possible to establish formulas whose application is valid not only at low pressures, but also up to pressures of a few bars, as will be explained below.

As far as thermal conductivity is concerned, it has been necessary in this monograph to develop more general formulas than those currently available, so as to represent, for any temperature, the experimental data for a gas or gas mixture.

This text should be read in conjunction with the articles Viscosity [K 480] and Effects of high and very high pressures. of this treatise, which shows the influence of pressure on the transport properties of gases.