Convection Problem
 

Hi all,

I'm working with a simulation of a Clusius-Dickel column, which use thermodiffusion and convection to separate the components of a gas mixture. In this type of column one has two concentric cilindres, one at higher temperature to create a temperature gradient along the radial direction. Usually the lighter component of the mixture agglomerate in the hot wall and the heavier in the cold wall. Then, due to convection the hot gas near the wall (in this case H2) goes up and the cold gas go down, generating a concentration gradient along the vertical axis. Unfortunately when I run the simulation the convection currents generated doesn't move the agglomerate species, they stay attached to the walls without movement. I don't understand why this happen; if someone could help me with some insight to the problem I would really appreciate it.

I attached some photos. Fig 1 is a scheme of the Clusius-Dickel column. Fig 2 shows the enrichment distribution (%) of molecular hydrogen. Fig 3 shows velocity vectors created by convection.

Kind Regards,

KsaMe