air entrainment - deaeration
 

Flow 3D has an air entrainment model based on the species mass transfer from air to liquid side. Can someone please advise how the deaeration process (i.e. at downstream of the air entrainment zone) is modeled in flow 3D?

Any references or short description of the model is appreciated.

Thanks,
John

De-aeration is handled by the Drift-Flux physics module.

Mostly Drift-Flux physics adds calculation of relative velocity between a dispersed phase (the bubbles) and a continuous phase (the liquid) using individual particle data (drag coefficient, radius, density) and also the Richardson-Zaki correlation for hindered drag up to about 40% or 50% concentration. By adding drift velocity to the N-S equations, separation and buoyancy effects are more accurately modeled.

Drift-Flux also includes an optional check box to "allow dispersed phase to escape at the free surface". This does just what it sounds like: dispersed phase (bubble) concentration leaves free surface cells.

The air escape algorithms were updated as of v10.1 to be more accurate. There are two Tech Notes on the Drift Flux physics implementation on the FLOW-3D User's Site, along with a Tech Note that describes the Air Entrainment physics.