[Benfa]

Hi,

I am simulalting the transient separation of H2 in air in a room. The rooms boundaries are walls. The volume is initilaized with air while in the lower volume (bottom of the room) h2 with a specifi mass fraction is initialized. The fluid is defined as variable mixture (H2 and air). Air is used as constraint while H2 is calculated with the transport equation. I also activated kinematic diffusivity for H2. Boyuoncy is activated as well.

Problem is that I do not observe the expected diffusion and density difference driven flow of H2 to the top of the room. Normally the h2 concentration at the top should increase.

Anyone who simulated a similar phenomena or did I anything wrong with the mixture?

Thanks in advance