[marsa27]

Hi,

I want to simulate the forming of a glass bottle

I would like to know if it possible use a degassing option for a multiphase VOF model (air and glass) to allow air to escape from the mold but not the glass?
In positive case how I can activate this option?
What kind of VOF model? Is enough a homogeneous VOF model?

Thanks

[Opaque]

If you want the phases to separate, i.e. different velocities at the same location, the model must be in-homogeneous.

Homogenous multiphase model --> shared field

[marsa27]

Originally Posted by Opaque

If you want the phases to separate, i.e. different velocities at the same location, the model must be in-homogeneous.

Homogenous multiphase model --> shared field

So in a dishomogeneous case is possible the degassification condition?
How I can active it?

[Opaque]

You have to check the documentation in detail. Specifically the outlet boundary condition for multiphase flow models.

From the documentation

2.5.1.9. Degassing Condition (Multiphase only)
Degassing boundary conditions are used to model a free surface from which dispersed bubbles are permitted to escape, but the liquid phase is not. They are useful for modeling flow in bubble columns.

When Degassing Boundary Condition is selected as the Flow Specification of an outlet, the continuous phase and any dispersed solid phases that may be present see this boundary as a free-slip wall and do not leave the domain. Dispersed fluid phases and Lagrange particles see this boundary as an outlet. However, the outlet pressure is not specified. Instead, a pressure distribution is computed on this fixed-position boundary, and can be interpreted as representing the weight of the surface height variations in the real flow.

Because the Degassing Boundary Condition does not specify a pressure value, a fixed pressure reference point will be set automatically for a domain with an incompressible flow with degassing boundaries, but no pressure boundaries.

[Gert-Jan]

In Pre, just define an outlet, there select the option 'Degassing Condition'.