FREE JET EXPANSIONS OF BINARY ATOMIC MIXTURES - A METHOD OF MOMENTS SOLUTION OF THE BOLTZMANN-EQUATION

The method of moments is used to obtain solutions to the Boltzmann equ ation describing flow and thermal relaxation of binary atomic mixtures undergoing adiabatic free jet expansion. Differential moment equation s are solved within the framework of an anisotropic Maxwellian distrib ution function. Numerical integration of these equations yields the te mporal dependence of the four moments of the distribution function for each flow component; density, hydrodynamic velocity, parallel tempera ture, and perpendicular temperature. Results are presented for mixture s of the rare gases which yield new insight into the driving forces be hind the phenomena of velocity and temperature slip. The model can eas ily be extended to ternary and higher atomic mixtures. (C) 1995 Americ an Institute of Physics.