It was recently discovered by E.W.Becker and his coworkers that an isotope gas mixture could be separated in a supersonic flow of jet.
The separation may be due to pressure diffusion caused by radial pressure gradient in the vicinity of nozzle opening when the Knudsen number Kn is much smaller than 10-1.
On the other hand, when Kn>> 10-1, it may be explained in terms of free molecular effusion of gas mixture at the nozzle opening, but in an intermediate regime, Kn10-1, theoretical treatment is difficult.
In this report, the correlation of separation effect εA, and cut η was given by the Eqs. (19) and (20), which were derived from the kinetic theory of gas, on the assumption that gas mixture effuses as free molecular flow at the nozzle opening.
The values calculated by the Eqs. (19) and (20) have been found in fairly good agreement with those experimental date which were obtained by Becker, et al. when the nozzle inlet pressure was maintained to be 30 Torr.