EFFECT OF GRAVITY AND INTERMOLECULAR POTENTIAL ON HE-3-HE-4 SEPARATIVE PERFORMANCES OF CRYOGENIC-WALL THERMAL-DIFFUSION COLUMN

The effect of gravity and intermolecular potential on He-3-He-4 separa tive performances of the thermal diffusion column were analysed by usi ng the two-dimensional rigorous numerical solution of convection-diffu sion equations with cold wall temperature T-c, pressure P and temperat ure difference Delta T between the hot and cold walls being parametric ally changed, while the feed flow rate F and the cut theta being a con stant 1 cm(3) min(-1) (converted at 288.15 K, 0.1 MPa) and 0.1, respec tively. On the moon, the optimum pressure P-opt, where the total separ ation factor alpha beta takes a maximum, is about root 6 times greater than that of the earth. The way in which the thermal diffusion factor alpha(T) varies with temperature depends on the intermolecular potent ial model. Therefore, separative performances of the thermal diffusion column vary according to the intermolecular potential with T-c and De lta T being changed. In design analyses, it is important to evaluate t he temperature dependence of alpha(T) of helium. (C) 1998 Elsevier Sci ence S.A. All rights reserved.