Estimation of the influence of gas velocity on the separation factor of a thermal diffusion column

The transport equation relevant to the heavier of two elements forming a gaseous mixture was derived from the following equations. Heat balance:d 2 T/dr 2+(l/r)·(dT/dr))= 0 Material balance:d 2 v 2+(l/r)·=α·(T-T c) Diffusion equation concerning the heavier element: σ(rJ c)/σz+σ(rJ DZ )σz+σ(rJ DR)/σrσ(rJ TD)/σr=0 Concentration of the heavier element in the radial direction: C 1(r,z)=C1+(R i,Z)+(r-R i)K 1. The transport equation thus derived became that of Jones & Furry when the smaller terms were neglected. The influence on the separation factor brought by the axial gas velocityv i along the hot wire surface was then analyzed. The results were as follows: The maximum separation factor displaces toward lower operating pressures when the gas velocity v i is increased to a certain degree. It would appear from the present calculation that to obtain maximum separation, lower operating pressures should be combined with higher gas velocity v i, while with increasing operating pressure, v i should have to be gradually reduced, finally to reach zero at a certain pressure.