Observations on flow fields generated by opposed free-jets of gas mixtures

Abstract

Spatial distributions of velocities in the neighborhood of the interference zone of nondiametrically opposed two-dimensional free-jets of argon–helium mixtures have been investigated using Doppler-shifted fluorescence radiation excited by an electron beam. Macroscopic velocities for each species were measured using a scanning Fabry–Perot interferometer system. Complementary spatial distributions of species mole fractions were determined using a mass flow probe, molecular beam sampling system, and quadrupole mass analyzer. Data were obtained over a wide range of experimental parameters, in particular, the reservoir to test region pressure ratio, 1.9 to 42, the Reynolds number based on reservoir conditions and jet width, 25 to 117, the mixture ratio, from 1% to 10% argon in helium, and the total included angle between jet axes, 120° and 90°. Detailed field plots of velocity and of mole fraction provide the basis for the construction of parameteric correlation functions for velocities and for compositions. Stage separation factors were calculated giving values comparable with those expected from ideal barrier separation processes. Processes of separation are discussed.