Purge helium in a pre-filled hydrogen tube in Ansys fluent (version 2019 r3)
 

Hi,

I am doing a study that purging helium in a pre-filled hydrogen tube. How can i set that up in Ansys?

Please read the section "Multiphase Model" in the manual first.

Phase
 

Are both in same phase, either gaseous or liquid? If yes, then all you need is to set up Species Transport, of course, without any reactions. Initialize with Hydrogen mass fraction of 1 and mass fraction of Helium as 1 at the inlet. Run it as transient.

How about the helium and the hydrogen with different velocity?

Gases
 

If you have two inlets, then, of course, you can set different velocities. As far as the field within the domain is concerned, Fluent does it based on first principles. So, if those are supposed to be flowing at different velocities, then you will observe that. However, gases reach same velocity quite fast.