Effect of Turbulence in Thermal Diffusion Columns

A certain amount of controlled turbulence improves markedly the separation factor and transport of thermal diffusion isotope separation columns. Measurements on this effect are reported for hot-wire columns 3 meters long, operating on argon gas, and with power input about 725 watts. At pressures three times that for onset of gene ral turbulence the separation factor qₑ is still 1.5. Spacers made of pairs of cross-wires of 40-mil Ni wire attached to the hot wire every 10 cm along its length raise the separation factor qₑ for optimum pressure from 9.1 to 27.2. If these spacers are attached every 5 cm, qₑ rises further to 36. The optimum pressure increases from 0.17 atmos (no spacers) to 0.28 atmos. Identical operation of a similar column with a plain hot wire but with slight constrictions every 15 cm in the cold wall gives qₑ=26.6. Introduction of these regularly spaced interruptions to the lamellar convective flow of the gas also increases the transport of the A³⁶ isotope to the top of the column. Some analysis of these effects is given.