How do I classify an Inlet Diverter/Deflector Device for Momentum Sizing Criteria 1

[Sirius P.Eng.]

I am currently verifying whether a 3-phase separator inlet nozzle is undersized or not based on momentum sizing criteria.
Now, the inlet device in question is an inlet diverter/deflector.

In the Shell DEP and Norsok standards for momentum sizing criteria, an inlet deflector is not mentioned. I'm I allowed to assume a half-open pipe then, for instance?. Please advise.

 

[georgeverghese]

A half open pipe is a deflector since the end of the pipe is blocked off / welded to an end plate.