A new device that divides the thermal-diffusion column into two passages by inserting a permeable-barrier resulting in improving the degree of separation of heavy water was investigated analytically. The theoretical model and analytical solution were obtained by using the variable separation with an orthogonal expansion technique in terms of power series. The theoretical predictions were represented graphically with the aspect ratio and channel thickness ratio parameters and compared with those obtained in the Clusius-Dickel column of the same working dimensions. Considerable improvement on heavy water enrichment was obtainable by employing such double-flow devices with inserting a permeable barrier, instead of using the Clusius-Dickel thermal-diffusion column. The effects of the permeable barrier locations as well as the aspect ratio, and channel thickness ratio on the separation efficiency enhancement of heavy water in double-flows thermal-diffusion columns have been also delineated.
