Extend fluid volume 3D nozzle
 

Hi, I have a 3D nozzle (imported from a CAD) with BCs of pressure outlet, so I decided to extend the volume domain to avoid reverse flow at the outlet.

Since I am new in fluent, I am not very experienced with this practise..

What is the best way to do that? I mean, can I create it in designModeler or must I do it in my CAD software? should I do boolean operations on the two volumes before meshing? and where should I impose the boundary condition of pressure outlet?

Thanks in advance :)

As per my understanding...
if you can model 3D nozzle in DM, then go for it (no de-featuring issue, which usually arise for complex geometries imported from CAD softwares), otherwise create extended geometry in CAD. yes, you have to do boolean operation to add them. and boundary condition will be imposed at end face of extended portion.

regards

I receive the geometry from a cad model (IGES or STEP file). Then, following your answer, I create a big fluid volume (for example 1m long) in DM after the nozzle outlet and I "merge" it with the nozzle outlet with a boolean operation, right?

The outlet BC pressure is 1 bar (absolute pressure) at the nozzle outlet. If I impose the BC to the "fake" outlet (the 1m longer one), what pressure must I impose?

Thanks