Theoretical Studies of Translational Nonequilibrium and Velocity Slip in a Freejet Expansion of a Binary Gas Mixture

Abstract

Parallel temperature of each species and velocity slip in a freejet of a binary rare gas mixture are numerically solved by using an ellipsoidal velocity distribution function, the moment method of the Boltzmann equation and by assuming the flow as a spherically symmetrical one. An attractive part of the Lennard-Jones (12, 6) potential is used as an intermolecular potential model. In order to simplify the calculation of collision terms between light and heavy species, an equal perpendicular temperature for each species and a very small velocity slip are assumed. It is obtained that the frozen parallel temperature of the heavy species is higher that of the light species. Also, the ratio of their frozen parallel temperatures and the terminal velocity slip increase by increasing the mass ratio and by decreasing the mole fraction of the heavy species.