[haitham]

Good day all

I have multiphase flow model with one fluid (oil+water) in gravity separator tank
how can i know the amount or volume of oil mixture in water
for flow 3D

second question, is there a way to know the oil concentration for example after 100 second from mixture

Thanks

[dmilano]

If you're using the 2-fluid model then the mixture concentration is defined by the fluid fraction. You can then measure the volume of each fluid using a sampling volume.

[haitham]

thanks a lot for your reply dmilano

Kindly if i define the initial fluid regions with appropriate densities (in model setup - initial)
fluid region 1 : water density 1000
fluid region 2 il density 800

and i have the rate of oil inside the water 5% , so how much define the fluid fraction for each fluid and where define it in initial or in boundary conditions?

thanks

[dmilano]

In two fluid problems the density is computed from the fluid fraction, not the other way around. If you define fluid 1 as water and fluid 2 as oil then you just specify the mixture fluid fraction in the initial conditions and at the boundaries. For example, if you had a mixture of 5% oil and 95% water entering at a boundary you would specify a fluid fraction of 0.95 at this location.

[haitham]

Dear dmilano

if i choose two number of fluid then there is no free surface (no out flow) in my case i have a free surface separator tank and the inlet flow is mixture between oil and water.
which the best model must be use
Drift flux
source mass
or
scalars

thanks alot

[dmilano]

Sorry - I didn't realize that there was a free surface. In this case you'll probably want to use the 1 fluid drift flux model and specify the mixture density at the boundaries, initial conditions, and sources.